Subject: bug#32194: [PATCH] Use Gnulib regex for lib-src

From: Paul Eggert <[email-masked]>
Date: Tue, 17 Jul 2018 16:47:29 -0700

Emacs regular expressions forked from everyone else long ago.
This makes it official and should allow simplification later.
etags.c now uses the glibc regex API, falling back on a
Gnulib-supplied substitute lib/regex.c if necessary.
Emacs proper now uses its own regular expression module.
Although this patch may look dauntingly large, most of it
was generated automatically by admin/merge-gnulib
and contains an exact copy of the glibc regex source,
and the by-hand changes do not grow the Emacs source code.
* .gitignore: Add .h files that the Gnulib regex code might generate.
* admin/merge-gnulib (GNULIB_MODULES): Add regex.
(AVOIDED_MODULES): Add 'lock'.
Do not remove m4/wint_t.m4, since Gnulib regex uses it.
* configure.ac (gt_TYPE_WINT_T, HAVE_LANGINFO_CODESET): Remove.
* lib-src/Makefile.in (regex.o): Remove; Gnulib does this for us now.
(etags_deps, etags_libs): Remove regex.o.
* lib-src/etags.c (add_regex): Use unsigned char translation array,
since glibc regex requires that.
* lib/Makefile.in (not_emacs_OBJECTS, for_emacs_OBJECTS): New macros.
(libegnu_a_OBJECTS): Use them, to avoid building e-regex.o.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib/btowc.c, lib/hard-locale.c, lib/hard-locale.h, lib/langinfo.in.h:
* lib/localcharset.c, lib/localcharset.h, lib/locale.in.h:
* lib/localeconv.c, lib/mbrtowc.c, lib/mbsinit.c, lib/mbtowc-impl.h:
* lib/mbtowc.c, lib/nl_langinfo.c, lib/regcomp.c, lib/regex.c:
* lib/regex.h, lib/regex_internal.c, lib/regex_internal.h:
* lib/regexec.c, lib/streq.h, lib/wchar.in.h, lib/wcrtomb.c:
* lib/wctype-h.c, lib/wctype.in.h:
* m4/btowc.m4, m4/builtin-expect.m4, m4/codeset.m4:
* m4/eealloc.m4, m4/glibc21.m4:
* m4/langinfo_h.m4, m4/localcharset.m4, m4/locale-fr.m4:
* m4/locale-ja.m4, m4/locale-zh.m4, m4/locale_h.m4:
* m4/localeconv.m4, m4/mbrtowc.m4, m4/mbsinit.m4:
* m4/mbstate_t.m4, m4/mbtowc.m4, m4/nl_langinfo.m4:
* m4/regex.m4, m4/wchar_h.m4, m4/wcrtomb.m4, m4/wctype_h.m4:
* m4/wint_t.m4:
New files, copied from Gnulib.
* src/regex-emacs.c, src/regex-emacs.h:
Rename from src/regex.c and src/regex.h, to avoid confusion
with lib/regex.c.  All references changed.
* src/regex-emacs.h, src/conf_post.h:
(RE_TRANSLATE_TYPE, RE_TRANSLATE, RE_TRANSLATE_P):
Move from src/conf_post.h to src/regex-emacs.h,
so that they don’t interfere with compiling lib/regex.c.
* test/src/regex-emacs-tests.el:
Rename from test/src/regex-tests.el, for consistency.
---
 .gitignore                                    |    4 +
 admin/MAINTAINERS                             |    2 +-
 admin/find-gc.el                              |    2 +-
 admin/merge-gnulib                            |    6 +-
 configure.ac                                  |   16 -
 etc/NEWS                                      |    7 +
 lib-src/Makefile.in                           |    8 +-
 lib-src/etags.c                               |    2 +-
 lib/Makefile.in                               |    8 +-
 lib/btowc.c                                   |   39 +
 lib/gnulib.mk.in                              |  549 +++
 lib/hard-locale.c                             |   72 +
 lib/hard-locale.h                             |   25 +
 lib/langinfo.in.h                             |  222 +
 lib/localcharset.c                            |  996 ++++
 lib/localcharset.h                            |  134 +
 lib/locale.in.h                               |  219 +
 lib/localeconv.c                              |  103 +
 lib/mbrtowc.c                                 |  458 ++
 lib/mbsinit.c                                 |   73 +
 lib/mbtowc-impl.h                             |   44 +
 lib/mbtowc.c                                  |   26 +
 lib/nl_langinfo.c                             |  366 ++
 lib/regcomp.c                                 | 3944 +++++++++++++++
 lib/regex.c                                   |   81 +
 lib/regex.h                                   |  658 +++
 lib/regex_internal.c                          | 1740 +++++++
 lib/regex_internal.h                          |  911 ++++
 lib/regexec.c                                 | 4324 +++++++++++++++++
 lib/streq.h                                   |  176 +
 lib/wchar.in.h                                | 1072 ++++
 lib/wcrtomb.c                                 |   53 +
 lib/wctype-h.c                                |    4 +
 lib/wctype.in.h                               |  533 ++
 lisp/char-fold.el                             |    2 +-
 m4/btowc.m4                                   |  120 +
 m4/builtin-expect.m4                          |   49 +
 m4/codeset.m4                                 |   24 +
 m4/eealloc.m4                                 |   31 +
 m4/glibc21.m4                                 |   34 +
 m4/gnulib-comp.m4                             |  299 ++
 m4/langinfo_h.m4                              |  120 +
 m4/localcharset.m4                            |   11 +
 m4/locale-fr.m4                               |  257 +
 m4/locale-ja.m4                               |  145 +
 m4/locale-zh.m4                               |  139 +
 m4/locale_h.m4                                |  122 +
 m4/localeconv.m4                              |   22 +
 m4/mbrtowc.m4                                 |  672 +++
 m4/mbsinit.m4                                 |   51 +
 m4/mbstate_t.m4                               |   41 +
 m4/mbtowc.m4                                  |   19 +
 m4/nl_langinfo.m4                             |   53 +
 m4/regex.m4                                   |  300 ++
 m4/wchar_h.m4                                 |  240 +
 m4/wcrtomb.m4                                 |  114 +
 m4/wctype_h.m4                                |  212 +
 m4/wint_t.m4                                  |   74 +
 src/Makefile.in                               |    2 +-
 src/casetab.c                                 |    2 +-
 src/conf_post.h                               |    7 -
 src/deps.mk                                   |   10 +-
 src/emacs.c                                   |    8 +-
 src/{regex.c => regex-emacs.c}                |   54 +-
 src/{regex.h => regex-emacs.h}                |   15 +-
 src/search.c                                  |    8 +-
 src/syntax.c                                  |    6 +-
 src/thread.h                                  |    2 +-
 .../{regex-tests.el => regex-emacs-tests.el}  |    6 +-
 69 files changed, 20057 insertions(+), 91 deletions(-)
 create mode 100644 lib/btowc.c
 create mode 100644 lib/hard-locale.c
 create mode 100644 lib/hard-locale.h
 create mode 100644 lib/langinfo.in.h
 create mode 100644 lib/localcharset.c
 create mode 100644 lib/localcharset.h
 create mode 100644 lib/locale.in.h
 create mode 100644 lib/localeconv.c
 create mode 100644 lib/mbrtowc.c
 create mode 100644 lib/mbsinit.c
 create mode 100644 lib/mbtowc-impl.h
 create mode 100644 lib/mbtowc.c
 create mode 100644 lib/nl_langinfo.c
 create mode 100644 lib/regcomp.c
 create mode 100644 lib/regex.c
 create mode 100644 lib/regex.h
 create mode 100644 lib/regex_internal.c
 create mode 100644 lib/regex_internal.h
 create mode 100644 lib/regexec.c
 create mode 100644 lib/streq.h
 create mode 100644 lib/wchar.in.h
 create mode 100644 lib/wcrtomb.c
 create mode 100644 lib/wctype-h.c
 create mode 100644 lib/wctype.in.h
 create mode 100644 m4/btowc.m4
 create mode 100644 m4/builtin-expect.m4
 create mode 100644 m4/codeset.m4
 create mode 100644 m4/eealloc.m4
 create mode 100644 m4/glibc21.m4
 create mode 100644 m4/langinfo_h.m4
 create mode 100644 m4/localcharset.m4
 create mode 100644 m4/locale-fr.m4
 create mode 100644 m4/locale-ja.m4
 create mode 100644 m4/locale-zh.m4
 create mode 100644 m4/locale_h.m4
 create mode 100644 m4/localeconv.m4
 create mode 100644 m4/mbrtowc.m4
 create mode 100644 m4/mbsinit.m4
 create mode 100644 m4/mbstate_t.m4
 create mode 100644 m4/mbtowc.m4
 create mode 100644 m4/nl_langinfo.m4
 create mode 100644 m4/regex.m4
 create mode 100644 m4/wchar_h.m4
 create mode 100644 m4/wcrtomb.m4
 create mode 100644 m4/wctype_h.m4
 create mode 100644 m4/wint_t.m4
 rename src/{regex.c => regex-emacs.c} (99%)
 rename src/{regex.h => regex-emacs.h} (98%)
 rename test/src/{regex-tests.el => regex-emacs-tests.el} (99%)

diff --git a/.gitignore b/.gitignore
index d3712b0d6c..2f94169e85 100644
--- a/.gitignore
+++ b/.gitignore
@@ -58,8 +58,10 @@ lib/fcntl.h
 lib/getopt.h
 lib/getopt-cdefs.h
 lib/inttypes.h
+lib/langinfo.h
 lib/libgnu.a
 lib/limits.h
+lib/locale.h
 lib/signal.h
 lib/std*.h
 !lib/std*.in.h
@@ -68,6 +70,8 @@ lib/string.h
 lib/sys/
 lib/time.h
 lib/unistd.h
+lib/wchar.h
+lib/wctype.h
 src/buildobj.h
 src/globals.h
 src/lisp.mk
diff --git a/admin/MAINTAINERS b/admin/MAINTAINERS
index 753a676e81..3ceff6585b 100644
--- a/admin/MAINTAINERS
+++ b/admin/MAINTAINERS
@@ -37,7 +37,7 @@ Kenichi Handa
 	Mule
 
 Stefan Monnier
-	src/regex.c
+	src/regex-emacs.c
 	src/syntax.c
 	src/keymap.c
 	font-lock/jit-lock/syntax
diff --git a/admin/find-gc.el b/admin/find-gc.el
index fb564039c7..e8cc113650 100644
--- a/admin/find-gc.el
+++ b/admin/find-gc.el
@@ -57,7 +57,7 @@ find-gc-source-files
     "keymap.c" "sysdep.c" "buffer.c" "filelock.c"
     "insdel.c" "marker.c" "minibuf.c" "fileio.c"
     "dired.c" "cmds.c" "casefiddle.c"
-    "indent.c" "search.c" "regex.c" "undo.c"
+    "indent.c" "search.c" "regex-emacs.c" "undo.c"
     "alloc.c" "data.c" "doc.c" "editfns.c"
     "callint.c" "eval.c" "fns.c" "print.c" "lread.c"
     "syntax.c" "unexcoff.c"
diff --git a/admin/merge-gnulib b/admin/merge-gnulib
index 39dfaee8f4..5814bd0ecf 100755
--- a/admin/merge-gnulib
+++ b/admin/merge-gnulib
@@ -37,7 +37,7 @@ GNULIB_MODULES=
   getloadavg getopt-gnu gettime gettimeofday gitlog-to-changelog
   ignore-value intprops largefile lstat
   manywarnings memrchr minmax mkostemp mktime nstrftime
-  pipe2 pselect pthread_sigmask putenv qcopy-acl readlink readlinkat
+  pipe2 pselect pthread_sigmask putenv qcopy-acl readlink readlinkat regex
   sig2str socklen stat-time std-gnu11 stdalign stddef stdio
   stpcpy strtoimax symlink sys_stat sys_time
   tempname time time_r time_rz timegm timer-time timespec-add timespec-sub
@@ -46,7 +46,7 @@ GNULIB_MODULES=
 '
 
 AVOIDED_MODULES='
-  close dup fchdir fstat
+  close dup fchdir fstat lock
   malloc-posix msvc-inval msvc-nothrow
   openat-die opendir raise
   save-cwd select setenv sigprocmask stat stdarg stdbool
@@ -107,7 +107,7 @@ avoided_flags=
       "$src"m4/gl-openssl.m4 \
       "$src"m4/gnulib-cache.m4 "$src"m4/gnulib-tool.m4 \
       "$src"m4/manywarnings-c++.m4 \
-      "$src"m4/warn-on-use.m4 "$src"m4/wint_t.m4 &&
+      "$src"m4/warn-on-use.m4 &&
 cp -- "$gnulib_srcdir"/build-aux/texinfo.tex "$src"doc/misc &&
 cp -- "$gnulib_srcdir"/build-aux/config.guess \
       "$gnulib_srcdir"/build-aux/config.sub \
diff --git a/configure.ac b/configure.ac
index b6918671e4..3bc843c5e3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -807,10 +807,6 @@ AC_DEFUN
 AC_CHECK_FUNCS_ONCE([putenv])
 AC_DEFUN([gl_FUNC_PUTENV],
   [test "$ac_cv_func_putenv" = yes || REPLACE_PUTENV=1])
-# Emacs does not use the wchar or wctype-h modules.
-AC_DEFUN([gt_TYPE_WINT_T],
-  [GNULIB_OVERRIDES_WINT_T=0
-   AC_SUBST([GNULIB_OVERRIDES_WINT_T])])
 
 # Initialize gnulib right after choosing the compiler.
 dnl Amongst other things, this sets AR and ARFLAGS.
@@ -4358,18 +4354,6 @@ AC_DEFUN
 fi
 AC_SUBST(XGSELOBJ)
 
-dnl Adapted from Haible's version.
-AC_CACHE_CHECK([for nl_langinfo and CODESET], emacs_cv_langinfo_codeset,
-  [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <langinfo.h>]],
-    [[char* cs = nl_langinfo(CODESET);]])],
-    emacs_cv_langinfo_codeset=yes,
-    emacs_cv_langinfo_codeset=no)
-  ])
-if test $emacs_cv_langinfo_codeset = yes; then
-  AC_DEFINE(HAVE_LANGINFO_CODESET, 1,
-    [Define if you have <langinfo.h> and nl_langinfo(CODESET).])
-fi
-
 AC_TYPE_MBSTATE_T
 
 dnl Fixme: AC_SYS_POSIX_TERMIOS should probably be used, but it's not clear
diff --git a/etc/NEWS b/etc/NEWS
index c0f380614a..3d9c930198 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -31,6 +31,13 @@ functions 'json-serialize', 'json-insert', 'json-parse-string', and
 'json-parse-buffer' are typically much faster than their Lisp
 counterparts from json.el.
 
+** The etags program now uses the C library's regular expression matcher
+when possible, and a compatible regex substitute otherwise.  This will
+let developers maintain Emacs's own regex code without having to also
+support other programs.  The new configure option '--without-included-regex'
+forces etags to use the C library's regex matcher even if the regex
+substitute ordinarily would be used to work around compatibility problems.
+
 ** Emacs has been ported to the -fcheck-pointer-bounds option of GCC.
 This causes Emacs to check bounds of some arrays addressed by its
 internal pointers, which can be helpful when debugging the Emacs
diff --git a/lib-src/Makefile.in b/lib-src/Makefile.in
index fa37d8ed85..b2b901788a 100644
--- a/lib-src/Makefile.in
+++ b/lib-src/Makefile.in
@@ -361,13 +361,9 @@ TAGS:
 ../lib/libgnu.a: $(config_h)
 	$(MAKE) -C ../lib all
 
-regex.o: $(srcdir)/../src/regex.c $(srcdir)/../src/regex.h $(config_h)
-	$(AM_V_CC)$(CC) -c $(CPP_CFLAGS) $<
-
-
-etags_deps = ${srcdir}/etags.c regex.o $(NTLIB) $(config_h)
+etags_deps = ${srcdir}/etags.c $(NTLIB) $(config_h)
 etags_cflags = -DEMACS_NAME="\"GNU Emacs\"" -DVERSION="\"${version}\"" -o $@
-etags_libs = regex.o $(NTLIB) $(LOADLIBES)
+etags_libs = $(NTLIB) $(LOADLIBES)
 
 etags${EXEEXT}: ${etags_deps}
 	$(AM_V_CCLD)$(CC) ${ALL_CFLAGS} $(etags_cflags) $< $(etags_libs)
diff --git a/lib-src/etags.c b/lib-src/etags.c
index b3b4575e0a..ee50670343 100644
--- a/lib-src/etags.c
+++ b/lib-src/etags.c
@@ -6401,7 +6401,7 @@ add_regex (char *regexp_pattern, language *lang)
   *patbuf = zeropattern;
   if (ignore_case)
     {
-      static char lc_trans[UCHAR_MAX + 1];
+      static unsigned char lc_trans[UCHAR_MAX + 1];
       int i;
       for (i = 0; i < UCHAR_MAX + 1; i++)
 	lc_trans[i] = c_tolower (i);
diff --git a/lib/Makefile.in b/lib/Makefile.in
index 201f4b5383..b26db27423 100644
--- a/lib/Makefile.in
+++ b/lib/Makefile.in
@@ -79,9 +79,15 @@ ../config.status:
 Makefile: ../config.status $(srcdir)/Makefile.in
 	$(MAKE) -C .. src/$@
 
+# Object modules that need not be built for Emacs.
+# Emacs does not need e-regex.o (it has its own regex-emacs.c),
+# and building it would just waste time.
+not_emacs_OBJECTS = regex.o
+
 libgnu_a_OBJECTS = $(gl_LIBOBJS) \
   $(patsubst %.c,%.o,$(filter %.c,$(libgnu_a_SOURCES)))
-libegnu_a_OBJECTS = $(patsubst %.o,e-%.o,$(libgnu_a_OBJECTS))
+for_emacs_OBJECTS = $(filter-out $(not_emacs_OBJECTS),$(libgnu_a_OBJECTS))
+libegnu_a_OBJECTS = $(patsubst %.o,e-%.o,$(for_emacs_OBJECTS))
 
 $(libegnu_a_OBJECTS) $(libgnu_a_OBJECTS): $(BUILT_SOURCES)
 
diff --git a/lib/btowc.c b/lib/btowc.c
new file mode 100644
index 0000000000..54124b28ac
--- /dev/null
+++ b/lib/btowc.c
@@ -0,0 +1,39 @@
+/* Convert unibyte character to wide character.
+   Copyright (C) 2008, 2010-2018 Free Software Foundation, Inc.
+   Written by Bruno Haible <[email-masked]>, 2008.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <wchar.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+wint_t
+btowc (int c)
+{
+  if (c != EOF)
+    {
+      char buf[1];
+      wchar_t wc;
+
+      buf[0] = c;
+      if (mbtowc (&wc, buf, 1) >= 0)
+        return wc;
+    }
+  return WEOF;
+}
diff --git a/lib/gnulib.mk.in b/lib/gnulib.mk.in
index e623921091..5fe9317766 100644
--- a/lib/gnulib.mk.in
+++ b/lib/gnulib.mk.in
@@ -38,6 +38,7 @@
 #  --avoid=dup \
 #  --avoid=fchdir \
 #  --avoid=fstat \
+#  --avoid=lock \
 #  --avoid=malloc-posix \
 #  --avoid=msvc-inval \
 #  --avoid=msvc-nothrow \
@@ -112,6 +113,7 @@
 #  qcopy-acl \
 #  readlink \
 #  readlinkat \
+#  regex \
 #  sig2str \
 #  socklen \
 #  stat-time \
@@ -215,6 +217,7 @@ GETOPT_CDEFS_H = @GETOPT_CDEFS_H@
 GETOPT_H = @GETOPT_H@
 GFILENOTIFY_CFLAGS = @GFILENOTIFY_CFLAGS@
 GFILENOTIFY_LIBS = @GFILENOTIFY_LIBS@
+GLIBC21 = @GLIBC21@
 GL_COND_LIBTOOL = @GL_COND_LIBTOOL@
 GL_GENERATE_ALLOCA_H = @GL_GENERATE_ALLOCA_H@
 GL_GENERATE_BYTESWAP_H = @GL_GENERATE_BYTESWAP_H@
@@ -227,6 +230,7 @@ GL_GENERATE_STDINT_H = @GL_GENERATE_STDINT_H@
 GMALLOC_OBJ = @GMALLOC_OBJ@
 GNULIB_ALPHASORT = @GNULIB_ALPHASORT@
 GNULIB_ATOLL = @GNULIB_ATOLL@
+GNULIB_BTOWC = @GNULIB_BTOWC@
 GNULIB_CALLOC_POSIX = @GNULIB_CALLOC_POSIX@
 GNULIB_CANONICALIZE_FILE_NAME = @GNULIB_CANONICALIZE_FILE_NAME@
 GNULIB_CHDIR = @GNULIB_CHDIR@
@@ -239,6 +243,7 @@ GNULIB_DPRINTF = @GNULIB_DPRINTF@
 GNULIB_DUP = @GNULIB_DUP@
 GNULIB_DUP2 = @GNULIB_DUP2@
 GNULIB_DUP3 = @GNULIB_DUP3@
+GNULIB_DUPLOCALE = @GNULIB_DUPLOCALE@
 GNULIB_ENVIRON = @GNULIB_ENVIRON@
 GNULIB_EUIDACCESS = @GNULIB_EUIDACCESS@
 GNULIB_EXPLICIT_BZERO = @GNULIB_EXPLICIT_BZERO@
@@ -297,24 +302,32 @@ GNULIB_GROUP_MEMBER = @GNULIB_GROUP_MEMBER@
 GNULIB_IMAXABS = @GNULIB_IMAXABS@
 GNULIB_IMAXDIV = @GNULIB_IMAXDIV@
 GNULIB_ISATTY = @GNULIB_ISATTY@
+GNULIB_ISWBLANK = @GNULIB_ISWBLANK@
+GNULIB_ISWCTYPE = @GNULIB_ISWCTYPE@
 GNULIB_LCHMOD = @GNULIB_LCHMOD@
 GNULIB_LCHOWN = @GNULIB_LCHOWN@
 GNULIB_LINK = @GNULIB_LINK@
 GNULIB_LINKAT = @GNULIB_LINKAT@
+GNULIB_LOCALECONV = @GNULIB_LOCALECONV@
 GNULIB_LOCALTIME = @GNULIB_LOCALTIME@
 GNULIB_LSEEK = @GNULIB_LSEEK@
 GNULIB_LSTAT = @GNULIB_LSTAT@
 GNULIB_MALLOC_POSIX = @GNULIB_MALLOC_POSIX@
+GNULIB_MBRLEN = @GNULIB_MBRLEN@
+GNULIB_MBRTOWC = @GNULIB_MBRTOWC@
 GNULIB_MBSCASECMP = @GNULIB_MBSCASECMP@
 GNULIB_MBSCASESTR = @GNULIB_MBSCASESTR@
 GNULIB_MBSCHR = @GNULIB_MBSCHR@
 GNULIB_MBSCSPN = @GNULIB_MBSCSPN@
+GNULIB_MBSINIT = @GNULIB_MBSINIT@
 GNULIB_MBSLEN = @GNULIB_MBSLEN@
 GNULIB_MBSNCASECMP = @GNULIB_MBSNCASECMP@
 GNULIB_MBSNLEN = @GNULIB_MBSNLEN@
+GNULIB_MBSNRTOWCS = @GNULIB_MBSNRTOWCS@
 GNULIB_MBSPBRK = @GNULIB_MBSPBRK@
 GNULIB_MBSPCASECMP = @GNULIB_MBSPCASECMP@
 GNULIB_MBSRCHR = @GNULIB_MBSRCHR@
+GNULIB_MBSRTOWCS = @GNULIB_MBSRTOWCS@
 GNULIB_MBSSEP = @GNULIB_MBSSEP@
 GNULIB_MBSSPN = @GNULIB_MBSSPN@
 GNULIB_MBSSTR = @GNULIB_MBSSTR@
@@ -336,6 +349,7 @@ GNULIB_MKSTEMP = @GNULIB_MKSTEMP@
 GNULIB_MKSTEMPS = @GNULIB_MKSTEMPS@
 GNULIB_MKTIME = @GNULIB_MKTIME@
 GNULIB_NANOSLEEP = @GNULIB_NANOSLEEP@
+GNULIB_NL_LANGINFO = @GNULIB_NL_LANGINFO@
 GNULIB_NONBLOCKING = @GNULIB_NONBLOCKING@
 GNULIB_OBSTACK_PRINTF = @GNULIB_OBSTACK_PRINTF@
 GNULIB_OBSTACK_PRINTF_POSIX = @GNULIB_OBSTACK_PRINTF_POSIX@
@@ -386,6 +400,7 @@ GNULIB_SECURE_GETENV = @GNULIB_SECURE_GETENV@
 GNULIB_SELECT = @GNULIB_SELECT@
 GNULIB_SETENV = @GNULIB_SETENV@
 GNULIB_SETHOSTNAME = @GNULIB_SETHOSTNAME@
+GNULIB_SETLOCALE = @GNULIB_SETLOCALE@
 GNULIB_SIGACTION = @GNULIB_SIGACTION@
 GNULIB_SIGNAL_H_SIGPIPE = @GNULIB_SIGNAL_H_SIGPIPE@
 GNULIB_SIGPROCMASK = @GNULIB_SIGPROCMASK@
@@ -425,6 +440,7 @@ GNULIB_TIMEGM = @GNULIB_TIMEGM@
 GNULIB_TIME_R = @GNULIB_TIME_R@
 GNULIB_TIME_RZ = @GNULIB_TIME_RZ@
 GNULIB_TMPFILE = @GNULIB_TMPFILE@
+GNULIB_TOWCTRANS = @GNULIB_TOWCTRANS@
 GNULIB_TRUNCATE = @GNULIB_TRUNCATE@
 GNULIB_TTYNAME_R = @GNULIB_TTYNAME_R@
 GNULIB_TZSET = @GNULIB_TZSET@
@@ -447,7 +463,43 @@ GNULIB_VSCANF = @GNULIB_VSCANF@
 GNULIB_VSNPRINTF = @GNULIB_VSNPRINTF@
 GNULIB_VSPRINTF_POSIX = @GNULIB_VSPRINTF_POSIX@
 GNULIB_WARN_CFLAGS = @GNULIB_WARN_CFLAGS@
+GNULIB_WCPCPY = @GNULIB_WCPCPY@
+GNULIB_WCPNCPY = @GNULIB_WCPNCPY@
+GNULIB_WCRTOMB = @GNULIB_WCRTOMB@
+GNULIB_WCSCASECMP = @GNULIB_WCSCASECMP@
+GNULIB_WCSCAT = @GNULIB_WCSCAT@
+GNULIB_WCSCHR = @GNULIB_WCSCHR@
+GNULIB_WCSCMP = @GNULIB_WCSCMP@
+GNULIB_WCSCOLL = @GNULIB_WCSCOLL@
+GNULIB_WCSCPY = @GNULIB_WCSCPY@
+GNULIB_WCSCSPN = @GNULIB_WCSCSPN@
+GNULIB_WCSDUP = @GNULIB_WCSDUP@
+GNULIB_WCSFTIME = @GNULIB_WCSFTIME@
+GNULIB_WCSLEN = @GNULIB_WCSLEN@
+GNULIB_WCSNCASECMP = @GNULIB_WCSNCASECMP@
+GNULIB_WCSNCAT = @GNULIB_WCSNCAT@
+GNULIB_WCSNCMP = @GNULIB_WCSNCMP@
+GNULIB_WCSNCPY = @GNULIB_WCSNCPY@
+GNULIB_WCSNLEN = @GNULIB_WCSNLEN@
+GNULIB_WCSNRTOMBS = @GNULIB_WCSNRTOMBS@
+GNULIB_WCSPBRK = @GNULIB_WCSPBRK@
+GNULIB_WCSRCHR = @GNULIB_WCSRCHR@
+GNULIB_WCSRTOMBS = @GNULIB_WCSRTOMBS@
+GNULIB_WCSSPN = @GNULIB_WCSSPN@
+GNULIB_WCSSTR = @GNULIB_WCSSTR@
+GNULIB_WCSTOK = @GNULIB_WCSTOK@
+GNULIB_WCSWIDTH = @GNULIB_WCSWIDTH@
+GNULIB_WCSXFRM = @GNULIB_WCSXFRM@
+GNULIB_WCTOB = @GNULIB_WCTOB@
 GNULIB_WCTOMB = @GNULIB_WCTOMB@
+GNULIB_WCTRANS = @GNULIB_WCTRANS@
+GNULIB_WCTYPE = @GNULIB_WCTYPE@
+GNULIB_WCWIDTH = @GNULIB_WCWIDTH@
+GNULIB_WMEMCHR = @GNULIB_WMEMCHR@
+GNULIB_WMEMCMP = @GNULIB_WMEMCMP@
+GNULIB_WMEMCPY = @GNULIB_WMEMCPY@
+GNULIB_WMEMMOVE = @GNULIB_WMEMMOVE@
+GNULIB_WMEMSET = @GNULIB_WMEMSET@
 GNULIB_WRITE = @GNULIB_WRITE@
 GNULIB__EXIT = @GNULIB__EXIT@
 GNUSTEP_CFLAGS = @GNUSTEP_CFLAGS@
@@ -463,10 +515,12 @@ GTK_OBJ = @GTK_OBJ@
 GZIP_PROG = @GZIP_PROG@
 HAVE_ALPHASORT = @HAVE_ALPHASORT@
 HAVE_ATOLL = @HAVE_ATOLL@
+HAVE_BTOWC = @HAVE_BTOWC@
 HAVE_C99_STDINT_H = @HAVE_C99_STDINT_H@
 HAVE_CANONICALIZE_FILE_NAME = @HAVE_CANONICALIZE_FILE_NAME@
 HAVE_CHOWN = @HAVE_CHOWN@
 HAVE_CLOSEDIR = @HAVE_CLOSEDIR@
+HAVE_CRTDEFS_H = @HAVE_CRTDEFS_H@
 HAVE_DECL_DIRFD = @HAVE_DECL_DIRFD@
 HAVE_DECL_ENVIRON = @HAVE_DECL_ENVIRON@
 HAVE_DECL_FCHDIR = @HAVE_DECL_FCHDIR@
@@ -506,10 +560,13 @@ HAVE_DECL_TRUNCATE = @HAVE_DECL_TRUNCATE@
 HAVE_DECL_TTYNAME_R = @HAVE_DECL_TTYNAME_R@
 HAVE_DECL_UNSETENV = @HAVE_DECL_UNSETENV@
 HAVE_DECL_VSNPRINTF = @HAVE_DECL_VSNPRINTF@
+HAVE_DECL_WCTOB = @HAVE_DECL_WCTOB@
+HAVE_DECL_WCWIDTH = @HAVE_DECL_WCWIDTH@
 HAVE_DIRENT_H = @HAVE_DIRENT_H@
 HAVE_DPRINTF = @HAVE_DPRINTF@
 HAVE_DUP2 = @HAVE_DUP2@
 HAVE_DUP3 = @HAVE_DUP3@
+HAVE_DUPLOCALE = @HAVE_DUPLOCALE@
 HAVE_EUIDACCESS = @HAVE_EUIDACCESS@
 HAVE_EXPLICIT_BZERO = @HAVE_EXPLICIT_BZERO@
 HAVE_FACCESSAT = @HAVE_FACCESSAT@
@@ -519,6 +576,7 @@ HAVE_FCHOWNAT = @HAVE_FCHOWNAT@
 HAVE_FCNTL = @HAVE_FCNTL@
 HAVE_FDATASYNC = @HAVE_FDATASYNC@
 HAVE_FDOPENDIR = @HAVE_FDOPENDIR@
+HAVE_FEATURES_H = @HAVE_FEATURES_H@
 HAVE_FFSL = @HAVE_FFSL@
 HAVE_FFSLL = @HAVE_FFSLL@
 HAVE_FSEEKO = @HAVE_FSEEKO@
@@ -539,6 +597,14 @@ HAVE_GRANTPT = @HAVE_GRANTPT@
 HAVE_GROUP_MEMBER = @HAVE_GROUP_MEMBER@
 HAVE_IMAXDIV_T = @HAVE_IMAXDIV_T@
 HAVE_INTTYPES_H = @HAVE_INTTYPES_H@
+HAVE_ISWBLANK = @HAVE_ISWBLANK@
+HAVE_ISWCNTRL = @HAVE_ISWCNTRL@
+HAVE_LANGINFO_ALTMON = @HAVE_LANGINFO_ALTMON@
+HAVE_LANGINFO_CODESET = @HAVE_LANGINFO_CODESET@
+HAVE_LANGINFO_ERA = @HAVE_LANGINFO_ERA@
+HAVE_LANGINFO_H = @HAVE_LANGINFO_H@
+HAVE_LANGINFO_T_FMT_AMPM = @HAVE_LANGINFO_T_FMT_AMPM@
+HAVE_LANGINFO_YESEXPR = @HAVE_LANGINFO_YESEXPR@
 HAVE_LCHMOD = @HAVE_LCHMOD@
 HAVE_LCHOWN = @HAVE_LCHOWN@
 HAVE_LINK = @HAVE_LINK@
@@ -547,7 +613,12 @@ HAVE_LONG_LONG_INT = @HAVE_LONG_LONG_INT@
 HAVE_LSTAT = @HAVE_LSTAT@
 HAVE_MAKEINFO = @HAVE_MAKEINFO@
 HAVE_MAX_ALIGN_T = @HAVE_MAX_ALIGN_T@
+HAVE_MBRLEN = @HAVE_MBRLEN@
+HAVE_MBRTOWC = @HAVE_MBRTOWC@
+HAVE_MBSINIT = @HAVE_MBSINIT@
 HAVE_MBSLEN = @HAVE_MBSLEN@
+HAVE_MBSNRTOWCS = @HAVE_MBSNRTOWCS@
+HAVE_MBSRTOWCS = @HAVE_MBSRTOWCS@
 HAVE_MEMCHR = @HAVE_MEMCHR@
 HAVE_MEMPCPY = @HAVE_MEMPCPY@
 HAVE_MKDIRAT = @HAVE_MKDIRAT@
@@ -562,6 +633,7 @@ HAVE_MKSTEMP = @HAVE_MKSTEMP@
 HAVE_MKSTEMPS = @HAVE_MKSTEMPS@
 HAVE_MODULES = @HAVE_MODULES@
 HAVE_NANOSLEEP = @HAVE_NANOSLEEP@
+HAVE_NL_LANGINFO = @HAVE_NL_LANGINFO@
 HAVE_OPENAT = @HAVE_OPENAT@
 HAVE_OPENDIR = @HAVE_OPENDIR@
 HAVE_OS_H = @HAVE_OS_H@
@@ -642,7 +714,44 @@ HAVE_VASPRINTF = @HAVE_VASPRINTF@
 HAVE_VDPRINTF = @HAVE_VDPRINTF@
 HAVE_WCHAR_H = @HAVE_WCHAR_H@
 HAVE_WCHAR_T = @HAVE_WCHAR_T@
+HAVE_WCPCPY = @HAVE_WCPCPY@
+HAVE_WCPNCPY = @HAVE_WCPNCPY@
+HAVE_WCRTOMB = @HAVE_WCRTOMB@
+HAVE_WCSCASECMP = @HAVE_WCSCASECMP@
+HAVE_WCSCAT = @HAVE_WCSCAT@
+HAVE_WCSCHR = @HAVE_WCSCHR@
+HAVE_WCSCMP = @HAVE_WCSCMP@
+HAVE_WCSCOLL = @HAVE_WCSCOLL@
+HAVE_WCSCPY = @HAVE_WCSCPY@
+HAVE_WCSCSPN = @HAVE_WCSCSPN@
+HAVE_WCSDUP = @HAVE_WCSDUP@
+HAVE_WCSFTIME = @HAVE_WCSFTIME@
+HAVE_WCSLEN = @HAVE_WCSLEN@
+HAVE_WCSNCASECMP = @HAVE_WCSNCASECMP@
+HAVE_WCSNCAT = @HAVE_WCSNCAT@
+HAVE_WCSNCMP = @HAVE_WCSNCMP@
+HAVE_WCSNCPY = @HAVE_WCSNCPY@
+HAVE_WCSNLEN = @HAVE_WCSNLEN@
+HAVE_WCSNRTOMBS = @HAVE_WCSNRTOMBS@
+HAVE_WCSPBRK = @HAVE_WCSPBRK@
+HAVE_WCSRCHR = @HAVE_WCSRCHR@
+HAVE_WCSRTOMBS = @HAVE_WCSRTOMBS@
+HAVE_WCSSPN = @HAVE_WCSSPN@
+HAVE_WCSSTR = @HAVE_WCSSTR@
+HAVE_WCSTOK = @HAVE_WCSTOK@
+HAVE_WCSWIDTH = @HAVE_WCSWIDTH@
+HAVE_WCSXFRM = @HAVE_WCSXFRM@
+HAVE_WCTRANS_T = @HAVE_WCTRANS_T@
+HAVE_WCTYPE_H = @HAVE_WCTYPE_H@
+HAVE_WCTYPE_T = @HAVE_WCTYPE_T@
 HAVE_WINSOCK2_H = @HAVE_WINSOCK2_H@
+HAVE_WINT_T = @HAVE_WINT_T@
+HAVE_WMEMCHR = @HAVE_WMEMCHR@
+HAVE_WMEMCMP = @HAVE_WMEMCMP@
+HAVE_WMEMCPY = @HAVE_WMEMCPY@
+HAVE_WMEMMOVE = @HAVE_WMEMMOVE@
+HAVE_WMEMSET = @HAVE_WMEMSET@
+HAVE_XLOCALE_H = @HAVE_XLOCALE_H@
 HAVE_XSERVER = @HAVE_XSERVER@
 HAVE__EXIT = @HAVE__EXIT@
 HYBRID_MALLOC = @HYBRID_MALLOC@
@@ -719,6 +828,11 @@ LIB_TIMER_TIME = @LIB_TIMER_TIME@
 LIB_WSOCK32 = @LIB_WSOCK32@
 LIMITS_H = @LIMITS_H@
 LN_S_FILEONLY = @LN_S_FILEONLY@
+LOCALCHARSET_TESTS_ENVIRONMENT = @LOCALCHARSET_TESTS_ENVIRONMENT@
+LOCALE_FR = @LOCALE_FR@
+LOCALE_FR_UTF8 = @LOCALE_FR_UTF8@
+LOCALE_JA = @LOCALE_JA@
+LOCALE_ZH_CN = @LOCALE_ZH_CN@
 LTLIBINTL = @LTLIBINTL@
 LTLIBOBJS = @LTLIBOBJS@
 M17N_FLT_CFLAGS = @M17N_FLT_CFLAGS@
@@ -733,7 +847,9 @@ NEXT_AS_FIRST_DIRECTIVE_ERRNO_H = @NEXT_AS_FIRST_DIRECTIVE_ERRNO_H@
 NEXT_AS_FIRST_DIRECTIVE_FCNTL_H = @NEXT_AS_FIRST_DIRECTIVE_FCNTL_H@
 NEXT_AS_FIRST_DIRECTIVE_GETOPT_H = @NEXT_AS_FIRST_DIRECTIVE_GETOPT_H@
 NEXT_AS_FIRST_DIRECTIVE_INTTYPES_H = @NEXT_AS_FIRST_DIRECTIVE_INTTYPES_H@
+NEXT_AS_FIRST_DIRECTIVE_LANGINFO_H = @NEXT_AS_FIRST_DIRECTIVE_LANGINFO_H@
 NEXT_AS_FIRST_DIRECTIVE_LIMITS_H = @NEXT_AS_FIRST_DIRECTIVE_LIMITS_H@
+NEXT_AS_FIRST_DIRECTIVE_LOCALE_H = @NEXT_AS_FIRST_DIRECTIVE_LOCALE_H@
 NEXT_AS_FIRST_DIRECTIVE_SIGNAL_H = @NEXT_AS_FIRST_DIRECTIVE_SIGNAL_H@
 NEXT_AS_FIRST_DIRECTIVE_STDDEF_H = @NEXT_AS_FIRST_DIRECTIVE_STDDEF_H@
 NEXT_AS_FIRST_DIRECTIVE_STDINT_H = @NEXT_AS_FIRST_DIRECTIVE_STDINT_H@
@@ -746,12 +862,16 @@ NEXT_AS_FIRST_DIRECTIVE_SYS_TIME_H = @NEXT_AS_FIRST_DIRECTIVE_SYS_TIME_H@
 NEXT_AS_FIRST_DIRECTIVE_SYS_TYPES_H = @NEXT_AS_FIRST_DIRECTIVE_SYS_TYPES_H@
 NEXT_AS_FIRST_DIRECTIVE_TIME_H = @NEXT_AS_FIRST_DIRECTIVE_TIME_H@
 NEXT_AS_FIRST_DIRECTIVE_UNISTD_H = @NEXT_AS_FIRST_DIRECTIVE_UNISTD_H@
+NEXT_AS_FIRST_DIRECTIVE_WCHAR_H = @NEXT_AS_FIRST_DIRECTIVE_WCHAR_H@
+NEXT_AS_FIRST_DIRECTIVE_WCTYPE_H = @NEXT_AS_FIRST_DIRECTIVE_WCTYPE_H@
 NEXT_DIRENT_H = @NEXT_DIRENT_H@
 NEXT_ERRNO_H = @NEXT_ERRNO_H@
 NEXT_FCNTL_H = @NEXT_FCNTL_H@
 NEXT_GETOPT_H = @NEXT_GETOPT_H@
 NEXT_INTTYPES_H = @NEXT_INTTYPES_H@
+NEXT_LANGINFO_H = @NEXT_LANGINFO_H@
 NEXT_LIMITS_H = @NEXT_LIMITS_H@
+NEXT_LOCALE_H = @NEXT_LOCALE_H@
 NEXT_SIGNAL_H = @NEXT_SIGNAL_H@
 NEXT_STDDEF_H = @NEXT_STDDEF_H@
 NEXT_STDINT_H = @NEXT_STDINT_H@
@@ -764,6 +884,8 @@ NEXT_SYS_TIME_H = @NEXT_SYS_TIME_H@
 NEXT_SYS_TYPES_H = @NEXT_SYS_TYPES_H@
 NEXT_TIME_H = @NEXT_TIME_H@
 NEXT_UNISTD_H = @NEXT_UNISTD_H@
+NEXT_WCHAR_H = @NEXT_WCHAR_H@
+NEXT_WCTYPE_H = @NEXT_WCTYPE_H@
 NOTIFY_CFLAGS = @NOTIFY_CFLAGS@
 NOTIFY_LIBS = @NOTIFY_LIBS@
 NOTIFY_OBJ = @NOTIFY_OBJ@
@@ -801,6 +923,7 @@ PTHREAD_H_DEFINES_STRUCT_TIMESPEC = @PTHREAD_H_DEFINES_STRUCT_TIMESPEC@
 PTRDIFF_T_SUFFIX = @PTRDIFF_T_SUFFIX@
 RALLOC_OBJ = @RALLOC_OBJ@
 RANLIB = @RANLIB@
+REPLACE_BTOWC = @REPLACE_BTOWC@
 REPLACE_CALLOC = @REPLACE_CALLOC@
 REPLACE_CANONICALIZE_FILE_NAME = @REPLACE_CANONICALIZE_FILE_NAME@
 REPLACE_CHOWN = @REPLACE_CHOWN@
@@ -811,6 +934,7 @@ REPLACE_DIRFD = @REPLACE_DIRFD@
 REPLACE_DPRINTF = @REPLACE_DPRINTF@
 REPLACE_DUP = @REPLACE_DUP@
 REPLACE_DUP2 = @REPLACE_DUP2@
+REPLACE_DUPLOCALE = @REPLACE_DUPLOCALE@
 REPLACE_FACCESSAT = @REPLACE_FACCESSAT@
 REPLACE_FCHOWNAT = @REPLACE_FCHOWNAT@
 REPLACE_FCLOSE = @REPLACE_FCLOSE@
@@ -841,14 +965,23 @@ REPLACE_GETPAGESIZE = @REPLACE_GETPAGESIZE@
 REPLACE_GETTIMEOFDAY = @REPLACE_GETTIMEOFDAY@
 REPLACE_GMTIME = @REPLACE_GMTIME@
 REPLACE_ISATTY = @REPLACE_ISATTY@
+REPLACE_ISWBLANK = @REPLACE_ISWBLANK@
+REPLACE_ISWCNTRL = @REPLACE_ISWCNTRL@
 REPLACE_LCHOWN = @REPLACE_LCHOWN@
 REPLACE_LINK = @REPLACE_LINK@
 REPLACE_LINKAT = @REPLACE_LINKAT@
+REPLACE_LOCALECONV = @REPLACE_LOCALECONV@
 REPLACE_LOCALTIME = @REPLACE_LOCALTIME@
 REPLACE_LOCALTIME_R = @REPLACE_LOCALTIME_R@
 REPLACE_LSEEK = @REPLACE_LSEEK@
 REPLACE_LSTAT = @REPLACE_LSTAT@
 REPLACE_MALLOC = @REPLACE_MALLOC@
+REPLACE_MBRLEN = @REPLACE_MBRLEN@
+REPLACE_MBRTOWC = @REPLACE_MBRTOWC@
+REPLACE_MBSINIT = @REPLACE_MBSINIT@
+REPLACE_MBSNRTOWCS = @REPLACE_MBSNRTOWCS@
+REPLACE_MBSRTOWCS = @REPLACE_MBSRTOWCS@
+REPLACE_MBSTATE_T = @REPLACE_MBSTATE_T@
 REPLACE_MBTOWC = @REPLACE_MBTOWC@
 REPLACE_MEMCHR = @REPLACE_MEMCHR@
 REPLACE_MEMMEM = @REPLACE_MEMMEM@
@@ -858,6 +991,7 @@ REPLACE_MKNOD = @REPLACE_MKNOD@
 REPLACE_MKSTEMP = @REPLACE_MKSTEMP@
 REPLACE_MKTIME = @REPLACE_MKTIME@
 REPLACE_NANOSLEEP = @REPLACE_NANOSLEEP@
+REPLACE_NL_LANGINFO = @REPLACE_NL_LANGINFO@
 REPLACE_NULL = @REPLACE_NULL@
 REPLACE_OBSTACK_PRINTF = @REPLACE_OBSTACK_PRINTF@
 REPLACE_OPEN = @REPLACE_OPEN@
@@ -887,6 +1021,7 @@ REPLACE_RENAMEAT = @REPLACE_RENAMEAT@
 REPLACE_RMDIR = @REPLACE_RMDIR@
 REPLACE_SELECT = @REPLACE_SELECT@
 REPLACE_SETENV = @REPLACE_SETENV@
+REPLACE_SETLOCALE = @REPLACE_SETLOCALE@
 REPLACE_SLEEP = @REPLACE_SLEEP@
 REPLACE_SNPRINTF = @REPLACE_SNPRINTF@
 REPLACE_SPRINTF = @REPLACE_SPRINTF@
@@ -909,11 +1044,13 @@ REPLACE_STRTOD = @REPLACE_STRTOD@
 REPLACE_STRTOIMAX = @REPLACE_STRTOIMAX@
 REPLACE_STRTOK_R = @REPLACE_STRTOK_R@
 REPLACE_STRTOUMAX = @REPLACE_STRTOUMAX@
+REPLACE_STRUCT_LCONV = @REPLACE_STRUCT_LCONV@
 REPLACE_STRUCT_TIMEVAL = @REPLACE_STRUCT_TIMEVAL@
 REPLACE_SYMLINK = @REPLACE_SYMLINK@
 REPLACE_SYMLINKAT = @REPLACE_SYMLINKAT@
 REPLACE_TIMEGM = @REPLACE_TIMEGM@
 REPLACE_TMPFILE = @REPLACE_TMPFILE@
+REPLACE_TOWLOWER = @REPLACE_TOWLOWER@
 REPLACE_TRUNCATE = @REPLACE_TRUNCATE@
 REPLACE_TTYNAME_R = @REPLACE_TTYNAME_R@
 REPLACE_TZSET = @REPLACE_TZSET@
@@ -928,7 +1065,14 @@ REPLACE_VFPRINTF = @REPLACE_VFPRINTF@
 REPLACE_VPRINTF = @REPLACE_VPRINTF@
 REPLACE_VSNPRINTF = @REPLACE_VSNPRINTF@
 REPLACE_VSPRINTF = @REPLACE_VSPRINTF@
+REPLACE_WCRTOMB = @REPLACE_WCRTOMB@
+REPLACE_WCSFTIME = @REPLACE_WCSFTIME@
+REPLACE_WCSNRTOMBS = @REPLACE_WCSNRTOMBS@
+REPLACE_WCSRTOMBS = @REPLACE_WCSRTOMBS@
+REPLACE_WCSWIDTH = @REPLACE_WCSWIDTH@
+REPLACE_WCTOB = @REPLACE_WCTOB@
 REPLACE_WCTOMB = @REPLACE_WCTOMB@
+REPLACE_WCWIDTH = @REPLACE_WCWIDTH@
 REPLACE_WRITE = @REPLACE_WRITE@
 RSVG_CFLAGS = @RSVG_CFLAGS@
 RSVG_LIBS = @RSVG_LIBS@
@@ -1021,19 +1165,34 @@ gameuser = @gameuser@
 gl_GNULIB_ENABLED_03e0aaad4cb89ca757653bd367a6ccb7 = @gl_GNULIB_ENABLED_03e0aaad4cb89ca757653bd367a6ccb7@
 gl_GNULIB_ENABLED_2049e887c7e5308faad27b3f894bb8c9 = @gl_GNULIB_ENABLED_2049e887c7e5308faad27b3f894bb8c9@
 gl_GNULIB_ENABLED_260941c0e5dc67ec9e87d1fb321c300b = @gl_GNULIB_ENABLED_260941c0e5dc67ec9e87d1fb321c300b@
+gl_GNULIB_ENABLED_30838f5439487421042f2225bed3af76 = @gl_GNULIB_ENABLED_30838f5439487421042f2225bed3af76@
+gl_GNULIB_ENABLED_37f71b604aa9c54446783d80f42fe547 = @gl_GNULIB_ENABLED_37f71b604aa9c54446783d80f42fe547@
+gl_GNULIB_ENABLED_3dcce957eadc896e63ab5f137947b410 = @gl_GNULIB_ENABLED_3dcce957eadc896e63ab5f137947b410@
 gl_GNULIB_ENABLED_5264294aa0a5557541b53c8c741f7f31 = @gl_GNULIB_ENABLED_5264294aa0a5557541b53c8c741f7f31@
 gl_GNULIB_ENABLED_6099e9737f757db36c47fa9d9f02e88c = @gl_GNULIB_ENABLED_6099e9737f757db36c47fa9d9f02e88c@
 gl_GNULIB_ENABLED_682e609604ccaac6be382e4ee3a4eaec = @gl_GNULIB_ENABLED_682e609604ccaac6be382e4ee3a4eaec@
 gl_GNULIB_ENABLED_a9786850e999ae65a836a6041e8e5ed1 = @gl_GNULIB_ENABLED_a9786850e999ae65a836a6041e8e5ed1@
 gl_GNULIB_ENABLED_be453cec5eecf5731a274f2de7f2db36 = @gl_GNULIB_ENABLED_be453cec5eecf5731a274f2de7f2db36@
+gl_GNULIB_ENABLED_btowc = @gl_GNULIB_ENABLED_btowc@
 gl_GNULIB_ENABLED_cloexec = @gl_GNULIB_ENABLED_cloexec@
 gl_GNULIB_ENABLED_dirfd = @gl_GNULIB_ENABLED_dirfd@
 gl_GNULIB_ENABLED_dosname = @gl_GNULIB_ENABLED_dosname@
 gl_GNULIB_ENABLED_euidaccess = @gl_GNULIB_ENABLED_euidaccess@
 gl_GNULIB_ENABLED_getdtablesize = @gl_GNULIB_ENABLED_getdtablesize@
 gl_GNULIB_ENABLED_getgroups = @gl_GNULIB_ENABLED_getgroups@
+gl_GNULIB_ENABLED_langinfo = @gl_GNULIB_ENABLED_langinfo@
+gl_GNULIB_ENABLED_localcharset = @gl_GNULIB_ENABLED_localcharset@
+gl_GNULIB_ENABLED_locale = @gl_GNULIB_ENABLED_locale@
+gl_GNULIB_ENABLED_localeconv = @gl_GNULIB_ENABLED_localeconv@
+gl_GNULIB_ENABLED_mbrtowc = @gl_GNULIB_ENABLED_mbrtowc@
+gl_GNULIB_ENABLED_mbsinit = @gl_GNULIB_ENABLED_mbsinit@
+gl_GNULIB_ENABLED_mbtowc = @gl_GNULIB_ENABLED_mbtowc@
+gl_GNULIB_ENABLED_nl_langinfo = @gl_GNULIB_ENABLED_nl_langinfo@
 gl_GNULIB_ENABLED_open = @gl_GNULIB_ENABLED_open@
+gl_GNULIB_ENABLED_streq = @gl_GNULIB_ENABLED_streq@
 gl_GNULIB_ENABLED_strtoll = @gl_GNULIB_ENABLED_strtoll@
+gl_GNULIB_ENABLED_wchar = @gl_GNULIB_ENABLED_wchar@
+gl_GNULIB_ENABLED_wcrtomb = @gl_GNULIB_ENABLED_wcrtomb@
 gl_LIBOBJS = @gl_LIBOBJS@
 gl_LTLIBOBJS = @gl_LTLIBOBJS@
 gltests_LIBOBJS = @gltests_LIBOBJS@
@@ -1164,6 +1323,19 @@ libgnu_a_SOURCES += binary-io.h binary-io.c
 endif
 ## end   gnulib module binary-io
 
+## begin gnulib module btowc
+ifeq (,$(OMIT_GNULIB_MODULE_btowc))
+
+ifneq (,$(gl_GNULIB_ENABLED_btowc))
+
+endif
+EXTRA_DIST += btowc.c
+
+EXTRA_libgnu_a_SOURCES += btowc.c
+
+endif
+## end   gnulib module btowc
+
 ## begin gnulib module byteswap
 ifeq (,$(OMIT_GNULIB_MODULE_byteswap))
 
@@ -1787,6 +1959,18 @@ EXTRA_libgnu_a_SOURCES += group-member.c
 endif
 ## end   gnulib module group-member
 
+## begin gnulib module hard-locale
+ifeq (,$(OMIT_GNULIB_MODULE_hard-locale))
+
+ifneq (,$(gl_GNULIB_ENABLED_30838f5439487421042f2225bed3af76))
+libgnu_a_SOURCES += hard-locale.c
+
+endif
+EXTRA_DIST += hard-locale.h
+
+endif
+## end   gnulib module hard-locale
+
 ## begin gnulib module ignore-value
 ifeq (,$(OMIT_GNULIB_MODULE_ignore-value))
 
@@ -1853,6 +2037,44 @@ EXTRA_DIST += inttypes.in.h
 endif
 ## end   gnulib module inttypes-incomplete
 
+## begin gnulib module langinfo
+ifeq (,$(OMIT_GNULIB_MODULE_langinfo))
+
+ifneq (,$(gl_GNULIB_ENABLED_langinfo))
+BUILT_SOURCES += langinfo.h
+
+# We need the following in order to create an empty placeholder for
+# <langinfo.h> when the system doesn't have one.
+langinfo.h: langinfo.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(WARN_ON_USE_H)
+	$(AM_V_GEN)rm -f $@-t $@ && \
+	{ echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */'; \
+	  sed -e 's|@''GUARD_PREFIX''@|GL|g' \
+	      -e 's|@''HAVE_LANGINFO_H''@|$(HAVE_LANGINFO_H)|g' \
+	      -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
+	      -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
+	      -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
+	      -e 's|@''NEXT_LANGINFO_H''@|$(NEXT_LANGINFO_H)|g' \
+	      -e 's/@''GNULIB_NL_LANGINFO''@/$(GNULIB_NL_LANGINFO)/g' \
+	      -e 's|@''HAVE_LANGINFO_CODESET''@|$(HAVE_LANGINFO_CODESET)|g' \
+	      -e 's|@''HAVE_LANGINFO_T_FMT_AMPM''@|$(HAVE_LANGINFO_T_FMT_AMPM)|g' \
+	      -e 's|@''HAVE_LANGINFO_ALTMON''@|$(HAVE_LANGINFO_ALTMON)|g' \
+	      -e 's|@''HAVE_LANGINFO_ERA''@|$(HAVE_LANGINFO_ERA)|g' \
+	      -e 's|@''HAVE_LANGINFO_YESEXPR''@|$(HAVE_LANGINFO_YESEXPR)|g' \
+	      -e 's|@''HAVE_NL_LANGINFO''@|$(HAVE_NL_LANGINFO)|g' \
+	      -e 's|@''REPLACE_NL_LANGINFO''@|$(REPLACE_NL_LANGINFO)|g' \
+	      -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
+	      -e '/definition of _GL_WARN_ON_USE/r $(WARN_ON_USE_H)' \
+	      < $(srcdir)/langinfo.in.h; \
+	} > $@-t && \
+	mv $@-t $@
+MOSTLYCLEANFILES += langinfo.h langinfo.h-t
+
+endif
+EXTRA_DIST += langinfo.in.h
+
+endif
+## end   gnulib module langinfo
+
 ## begin gnulib module limits-h
 ifeq (,$(OMIT_GNULIB_MODULE_limits-h))
 
@@ -1883,6 +2105,70 @@ EXTRA_DIST += limits.in.h
 endif
 ## end   gnulib module limits-h
 
+## begin gnulib module localcharset
+ifeq (,$(OMIT_GNULIB_MODULE_localcharset))
+
+ifneq (,$(gl_GNULIB_ENABLED_localcharset))
+libgnu_a_SOURCES += localcharset.c
+
+endif
+EXTRA_DIST += localcharset.h
+
+endif
+## end   gnulib module localcharset
+
+## begin gnulib module locale
+ifeq (,$(OMIT_GNULIB_MODULE_locale))
+
+ifneq (,$(gl_GNULIB_ENABLED_locale))
+BUILT_SOURCES += locale.h
+
+# We need the following in order to create <locale.h> when the system
+# doesn't have one that provides all definitions.
+locale.h: locale.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H) $(WARN_ON_USE_H)
+	$(AM_V_GEN)rm -f $@-t $@ && \
+	{ echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */' && \
+	  sed -e 's|@''GUARD_PREFIX''@|GL|g' \
+	      -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
+	      -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
+	      -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
+	      -e 's|@''NEXT_LOCALE_H''@|$(NEXT_LOCALE_H)|g' \
+	      -e 's/@''GNULIB_LOCALECONV''@/$(GNULIB_LOCALECONV)/g' \
+	      -e 's/@''GNULIB_SETLOCALE''@/$(GNULIB_SETLOCALE)/g' \
+	      -e 's/@''GNULIB_DUPLOCALE''@/$(GNULIB_DUPLOCALE)/g' \
+	      -e 's|@''HAVE_DUPLOCALE''@|$(HAVE_DUPLOCALE)|g' \
+	      -e 's|@''HAVE_XLOCALE_H''@|$(HAVE_XLOCALE_H)|g' \
+	      -e 's|@''REPLACE_LOCALECONV''@|$(REPLACE_LOCALECONV)|g' \
+	      -e 's|@''REPLACE_SETLOCALE''@|$(REPLACE_SETLOCALE)|g' \
+	      -e 's|@''REPLACE_DUPLOCALE''@|$(REPLACE_DUPLOCALE)|g' \
+	      -e 's|@''REPLACE_STRUCT_LCONV''@|$(REPLACE_STRUCT_LCONV)|g' \
+	      -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
+	      -e '/definition of _GL_ARG_NONNULL/r $(ARG_NONNULL_H)' \
+	      -e '/definition of _GL_WARN_ON_USE/r $(WARN_ON_USE_H)' \
+	      < $(srcdir)/locale.in.h; \
+	} > $@-t && \
+	mv $@-t $@
+MOSTLYCLEANFILES += locale.h locale.h-t
+
+endif
+EXTRA_DIST += locale.in.h
+
+endif
+## end   gnulib module locale
+
+## begin gnulib module localeconv
+ifeq (,$(OMIT_GNULIB_MODULE_localeconv))
+
+ifneq (,$(gl_GNULIB_ENABLED_localeconv))
+
+endif
+EXTRA_DIST += localeconv.c
+
+EXTRA_libgnu_a_SOURCES += localeconv.c
+
+endif
+## end   gnulib module localeconv
+
 ## begin gnulib module localtime-buffer
 ifeq (,$(OMIT_GNULIB_MODULE_localtime-buffer))
 
@@ -1907,6 +2193,45 @@ EXTRA_libgnu_a_SOURCES += lstat.c
 endif
 ## end   gnulib module lstat
 
+## begin gnulib module mbrtowc
+ifeq (,$(OMIT_GNULIB_MODULE_mbrtowc))
+
+ifneq (,$(gl_GNULIB_ENABLED_mbrtowc))
+
+endif
+EXTRA_DIST += mbrtowc.c
+
+EXTRA_libgnu_a_SOURCES += mbrtowc.c
+
+endif
+## end   gnulib module mbrtowc
+
+## begin gnulib module mbsinit
+ifeq (,$(OMIT_GNULIB_MODULE_mbsinit))
+
+ifneq (,$(gl_GNULIB_ENABLED_mbsinit))
+
+endif
+EXTRA_DIST += mbsinit.c
+
+EXTRA_libgnu_a_SOURCES += mbsinit.c
+
+endif
+## end   gnulib module mbsinit
+
+## begin gnulib module mbtowc
+ifeq (,$(OMIT_GNULIB_MODULE_mbtowc))
+
+ifneq (,$(gl_GNULIB_ENABLED_mbtowc))
+
+endif
+EXTRA_DIST += mbtowc-impl.h mbtowc.c
+
+EXTRA_libgnu_a_SOURCES += mbtowc.c
+
+endif
+## end   gnulib module mbtowc
+
 ## begin gnulib module memrchr
 ifeq (,$(OMIT_GNULIB_MODULE_memrchr))
 
@@ -1961,6 +2286,19 @@ EXTRA_libgnu_a_SOURCES += mktime.c
 endif
 ## end   gnulib module mktime-internal
 
+## begin gnulib module nl_langinfo
+ifeq (,$(OMIT_GNULIB_MODULE_nl_langinfo))
+
+ifneq (,$(gl_GNULIB_ENABLED_nl_langinfo))
+
+endif
+EXTRA_DIST += nl_langinfo.c
+
+EXTRA_libgnu_a_SOURCES += nl_langinfo.c
+
+endif
+## end   gnulib module nl_langinfo
+
 ## begin gnulib module nstrftime
 ifeq (,$(OMIT_GNULIB_MODULE_nstrftime))
 
@@ -2066,6 +2404,17 @@ EXTRA_libgnu_a_SOURCES += at-func.c readlinkat.c
 endif
 ## end   gnulib module readlinkat
 
+## begin gnulib module regex
+ifeq (,$(OMIT_GNULIB_MODULE_regex))
+
+
+EXTRA_DIST += regcomp.c regex.c regex.h regex_internal.c regex_internal.h regexec.c
+
+EXTRA_libgnu_a_SOURCES += regcomp.c regex.c regex_internal.c regexec.c
+
+endif
+## end   gnulib module regex
+
 ## begin gnulib module root-uid
 ifeq (,$(OMIT_GNULIB_MODULE_root-uid))
 
@@ -2563,6 +2912,17 @@ EXTRA_libgnu_a_SOURCES += stpcpy.c
 endif
 ## end   gnulib module stpcpy
 
+## begin gnulib module streq
+ifeq (,$(OMIT_GNULIB_MODULE_streq))
+
+ifneq (,$(gl_GNULIB_ENABLED_streq))
+
+endif
+EXTRA_DIST += streq.h
+
+endif
+## end   gnulib module streq
+
 ## begin gnulib module string
 ifeq (,$(OMIT_GNULIB_MODULE_string))
 
@@ -3210,6 +3570,195 @@ EXTRA_DIST += vla.h
 endif
 ## end   gnulib module vla
 
+## begin gnulib module wchar
+ifeq (,$(OMIT_GNULIB_MODULE_wchar))
+
+ifneq (,$(gl_GNULIB_ENABLED_wchar))
+BUILT_SOURCES += wchar.h
+
+# We need the following in order to create <wchar.h> when the system
+# version does not work standalone.
+wchar.h: wchar.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H) $(WARN_ON_USE_H)
+	$(AM_V_GEN)rm -f $@-t $@ && \
+	{ echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */'; \
+	  sed -e 's|@''GUARD_PREFIX''@|GL|g' \
+	      -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
+	      -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
+	      -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
+	      -e 's|@''HAVE_FEATURES_H''@|$(HAVE_FEATURES_H)|g' \
+	      -e 's|@''NEXT_WCHAR_H''@|$(NEXT_WCHAR_H)|g' \
+	      -e 's|@''HAVE_WCHAR_H''@|$(HAVE_WCHAR_H)|g' \
+	      -e 's/@''HAVE_CRTDEFS_H''@/$(HAVE_CRTDEFS_H)/g' \
+	      -e 's/@''GNULIB_OVERRIDES_WINT_T''@/$(GNULIB_OVERRIDES_WINT_T)/g' \
+	      -e 's/@''GNULIB_BTOWC''@/$(GNULIB_BTOWC)/g' \
+	      -e 's/@''GNULIB_WCTOB''@/$(GNULIB_WCTOB)/g' \
+	      -e 's/@''GNULIB_MBSINIT''@/$(GNULIB_MBSINIT)/g' \
+	      -e 's/@''GNULIB_MBRTOWC''@/$(GNULIB_MBRTOWC)/g' \
+	      -e 's/@''GNULIB_MBRLEN''@/$(GNULIB_MBRLEN)/g' \
+	      -e 's/@''GNULIB_MBSRTOWCS''@/$(GNULIB_MBSRTOWCS)/g' \
+	      -e 's/@''GNULIB_MBSNRTOWCS''@/$(GNULIB_MBSNRTOWCS)/g' \
+	      -e 's/@''GNULIB_WCRTOMB''@/$(GNULIB_WCRTOMB)/g' \
+	      -e 's/@''GNULIB_WCSRTOMBS''@/$(GNULIB_WCSRTOMBS)/g' \
+	      -e 's/@''GNULIB_WCSNRTOMBS''@/$(GNULIB_WCSNRTOMBS)/g' \
+	      -e 's/@''GNULIB_WCWIDTH''@/$(GNULIB_WCWIDTH)/g' \
+	      -e 's/@''GNULIB_WMEMCHR''@/$(GNULIB_WMEMCHR)/g' \
+	      -e 's/@''GNULIB_WMEMCMP''@/$(GNULIB_WMEMCMP)/g' \
+	      -e 's/@''GNULIB_WMEMCPY''@/$(GNULIB_WMEMCPY)/g' \
+	      -e 's/@''GNULIB_WMEMMOVE''@/$(GNULIB_WMEMMOVE)/g' \
+	      -e 's/@''GNULIB_WMEMSET''@/$(GNULIB_WMEMSET)/g' \
+	      -e 's/@''GNULIB_WCSLEN''@/$(GNULIB_WCSLEN)/g' \
+	      -e 's/@''GNULIB_WCSNLEN''@/$(GNULIB_WCSNLEN)/g' \
+	      -e 's/@''GNULIB_WCSCPY''@/$(GNULIB_WCSCPY)/g' \
+	      -e 's/@''GNULIB_WCPCPY''@/$(GNULIB_WCPCPY)/g' \
+	      -e 's/@''GNULIB_WCSNCPY''@/$(GNULIB_WCSNCPY)/g' \
+	      -e 's/@''GNULIB_WCPNCPY''@/$(GNULIB_WCPNCPY)/g' \
+	      -e 's/@''GNULIB_WCSCAT''@/$(GNULIB_WCSCAT)/g' \
+	      -e 's/@''GNULIB_WCSNCAT''@/$(GNULIB_WCSNCAT)/g' \
+	      -e 's/@''GNULIB_WCSCMP''@/$(GNULIB_WCSCMP)/g' \
+	      -e 's/@''GNULIB_WCSNCMP''@/$(GNULIB_WCSNCMP)/g' \
+	      -e 's/@''GNULIB_WCSCASECMP''@/$(GNULIB_WCSCASECMP)/g' \
+	      -e 's/@''GNULIB_WCSNCASECMP''@/$(GNULIB_WCSNCASECMP)/g' \
+	      -e 's/@''GNULIB_WCSCOLL''@/$(GNULIB_WCSCOLL)/g' \
+	      -e 's/@''GNULIB_WCSXFRM''@/$(GNULIB_WCSXFRM)/g' \
+	      -e 's/@''GNULIB_WCSDUP''@/$(GNULIB_WCSDUP)/g' \
+	      -e 's/@''GNULIB_WCSCHR''@/$(GNULIB_WCSCHR)/g' \
+	      -e 's/@''GNULIB_WCSRCHR''@/$(GNULIB_WCSRCHR)/g' \
+	      -e 's/@''GNULIB_WCSCSPN''@/$(GNULIB_WCSCSPN)/g' \
+	      -e 's/@''GNULIB_WCSSPN''@/$(GNULIB_WCSSPN)/g' \
+	      -e 's/@''GNULIB_WCSPBRK''@/$(GNULIB_WCSPBRK)/g' \
+	      -e 's/@''GNULIB_WCSSTR''@/$(GNULIB_WCSSTR)/g' \
+	      -e 's/@''GNULIB_WCSTOK''@/$(GNULIB_WCSTOK)/g' \
+	      -e 's/@''GNULIB_WCSWIDTH''@/$(GNULIB_WCSWIDTH)/g' \
+	      -e 's/@''GNULIB_WCSFTIME''@/$(GNULIB_WCSFTIME)/g' \
+	      < $(srcdir)/wchar.in.h | \
+	  sed -e 's|@''HAVE_WINT_T''@|$(HAVE_WINT_T)|g' \
+	      -e 's|@''HAVE_BTOWC''@|$(HAVE_BTOWC)|g' \
+	      -e 's|@''HAVE_MBSINIT''@|$(HAVE_MBSINIT)|g' \
+	      -e 's|@''HAVE_MBRTOWC''@|$(HAVE_MBRTOWC)|g' \
+	      -e 's|@''HAVE_MBRLEN''@|$(HAVE_MBRLEN)|g' \
+	      -e 's|@''HAVE_MBSRTOWCS''@|$(HAVE_MBSRTOWCS)|g' \
+	      -e 's|@''HAVE_MBSNRTOWCS''@|$(HAVE_MBSNRTOWCS)|g' \
+	      -e 's|@''HAVE_WCRTOMB''@|$(HAVE_WCRTOMB)|g' \
+	      -e 's|@''HAVE_WCSRTOMBS''@|$(HAVE_WCSRTOMBS)|g' \
+	      -e 's|@''HAVE_WCSNRTOMBS''@|$(HAVE_WCSNRTOMBS)|g' \
+	      -e 's|@''HAVE_WMEMCHR''@|$(HAVE_WMEMCHR)|g' \
+	      -e 's|@''HAVE_WMEMCMP''@|$(HAVE_WMEMCMP)|g' \
+	      -e 's|@''HAVE_WMEMCPY''@|$(HAVE_WMEMCPY)|g' \
+	      -e 's|@''HAVE_WMEMMOVE''@|$(HAVE_WMEMMOVE)|g' \
+	      -e 's|@''HAVE_WMEMSET''@|$(HAVE_WMEMSET)|g' \
+	      -e 's|@''HAVE_WCSLEN''@|$(HAVE_WCSLEN)|g' \
+	      -e 's|@''HAVE_WCSNLEN''@|$(HAVE_WCSNLEN)|g' \
+	      -e 's|@''HAVE_WCSCPY''@|$(HAVE_WCSCPY)|g' \
+	      -e 's|@''HAVE_WCPCPY''@|$(HAVE_WCPCPY)|g' \
+	      -e 's|@''HAVE_WCSNCPY''@|$(HAVE_WCSNCPY)|g' \
+	      -e 's|@''HAVE_WCPNCPY''@|$(HAVE_WCPNCPY)|g' \
+	      -e 's|@''HAVE_WCSCAT''@|$(HAVE_WCSCAT)|g' \
+	      -e 's|@''HAVE_WCSNCAT''@|$(HAVE_WCSNCAT)|g' \
+	      -e 's|@''HAVE_WCSCMP''@|$(HAVE_WCSCMP)|g' \
+	      -e 's|@''HAVE_WCSNCMP''@|$(HAVE_WCSNCMP)|g' \
+	      -e 's|@''HAVE_WCSCASECMP''@|$(HAVE_WCSCASECMP)|g' \
+	      -e 's|@''HAVE_WCSNCASECMP''@|$(HAVE_WCSNCASECMP)|g' \
+	      -e 's|@''HAVE_WCSCOLL''@|$(HAVE_WCSCOLL)|g' \
+	      -e 's|@''HAVE_WCSXFRM''@|$(HAVE_WCSXFRM)|g' \
+	      -e 's|@''HAVE_WCSDUP''@|$(HAVE_WCSDUP)|g' \
+	      -e 's|@''HAVE_WCSCHR''@|$(HAVE_WCSCHR)|g' \
+	      -e 's|@''HAVE_WCSRCHR''@|$(HAVE_WCSRCHR)|g' \
+	      -e 's|@''HAVE_WCSCSPN''@|$(HAVE_WCSCSPN)|g' \
+	      -e 's|@''HAVE_WCSSPN''@|$(HAVE_WCSSPN)|g' \
+	      -e 's|@''HAVE_WCSPBRK''@|$(HAVE_WCSPBRK)|g' \
+	      -e 's|@''HAVE_WCSSTR''@|$(HAVE_WCSSTR)|g' \
+	      -e 's|@''HAVE_WCSTOK''@|$(HAVE_WCSTOK)|g' \
+	      -e 's|@''HAVE_WCSWIDTH''@|$(HAVE_WCSWIDTH)|g' \
+	      -e 's|@''HAVE_WCSFTIME''@|$(HAVE_WCSFTIME)|g' \
+	      -e 's|@''HAVE_DECL_WCTOB''@|$(HAVE_DECL_WCTOB)|g' \
+	      -e 's|@''HAVE_DECL_WCWIDTH''@|$(HAVE_DECL_WCWIDTH)|g' \
+	  | \
+	  sed -e 's|@''REPLACE_MBSTATE_T''@|$(REPLACE_MBSTATE_T)|g' \
+	      -e 's|@''REPLACE_BTOWC''@|$(REPLACE_BTOWC)|g' \
+	      -e 's|@''REPLACE_WCTOB''@|$(REPLACE_WCTOB)|g' \
+	      -e 's|@''REPLACE_MBSINIT''@|$(REPLACE_MBSINIT)|g' \
+	      -e 's|@''REPLACE_MBRTOWC''@|$(REPLACE_MBRTOWC)|g' \
+	      -e 's|@''REPLACE_MBRLEN''@|$(REPLACE_MBRLEN)|g' \
+	      -e 's|@''REPLACE_MBSRTOWCS''@|$(REPLACE_MBSRTOWCS)|g' \
+	      -e 's|@''REPLACE_MBSNRTOWCS''@|$(REPLACE_MBSNRTOWCS)|g' \
+	      -e 's|@''REPLACE_WCRTOMB''@|$(REPLACE_WCRTOMB)|g' \
+	      -e 's|@''REPLACE_WCSRTOMBS''@|$(REPLACE_WCSRTOMBS)|g' \
+	      -e 's|@''REPLACE_WCSNRTOMBS''@|$(REPLACE_WCSNRTOMBS)|g' \
+	      -e 's|@''REPLACE_WCWIDTH''@|$(REPLACE_WCWIDTH)|g' \
+	      -e 's|@''REPLACE_WCSWIDTH''@|$(REPLACE_WCSWIDTH)|g' \
+	      -e 's|@''REPLACE_WCSFTIME''@|$(REPLACE_WCSFTIME)|g' \
+	      -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
+	      -e '/definition of _GL_ARG_NONNULL/r $(ARG_NONNULL_H)' \
+	      -e '/definition of _GL_WARN_ON_USE/r $(WARN_ON_USE_H)'; \
+	} > $@-t && \
+	mv $@-t $@
+MOSTLYCLEANFILES += wchar.h wchar.h-t
+
+endif
+EXTRA_DIST += wchar.in.h
+
+endif
+## end   gnulib module wchar
+
+## begin gnulib module wcrtomb
+ifeq (,$(OMIT_GNULIB_MODULE_wcrtomb))
+
+ifneq (,$(gl_GNULIB_ENABLED_wcrtomb))
+
+endif
+EXTRA_DIST += wcrtomb.c
+
+EXTRA_libgnu_a_SOURCES += wcrtomb.c
+
+endif
+## end   gnulib module wcrtomb
+
+## begin gnulib module wctype-h
+ifeq (,$(OMIT_GNULIB_MODULE_wctype-h))
+
+ifneq (,$(gl_GNULIB_ENABLED_3dcce957eadc896e63ab5f137947b410))
+BUILT_SOURCES += wctype.h
+libgnu_a_SOURCES += wctype-h.c
+
+# We need the following in order to create <wctype.h> when the system
+# doesn't have one that works with the given compiler.
+wctype.h: wctype.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(WARN_ON_USE_H)
+	$(AM_V_GEN)rm -f $@-t $@ && \
+	{ echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */'; \
+	  sed -e 's|@''GUARD_PREFIX''@|GL|g' \
+	      -e 's/@''HAVE_WCTYPE_H''@/$(HAVE_WCTYPE_H)/g' \
+	      -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
+	      -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
+	      -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
+	      -e 's|@''NEXT_WCTYPE_H''@|$(NEXT_WCTYPE_H)|g' \
+	      -e 's/@''HAVE_CRTDEFS_H''@/$(HAVE_CRTDEFS_H)/g' \
+	      -e 's/@''GNULIB_OVERRIDES_WINT_T''@/$(GNULIB_OVERRIDES_WINT_T)/g' \
+	      -e 's/@''GNULIB_ISWBLANK''@/$(GNULIB_ISWBLANK)/g' \
+	      -e 's/@''GNULIB_WCTYPE''@/$(GNULIB_WCTYPE)/g' \
+	      -e 's/@''GNULIB_ISWCTYPE''@/$(GNULIB_ISWCTYPE)/g' \
+	      -e 's/@''GNULIB_WCTRANS''@/$(GNULIB_WCTRANS)/g' \
+	      -e 's/@''GNULIB_TOWCTRANS''@/$(GNULIB_TOWCTRANS)/g' \
+	      -e 's/@''HAVE_ISWBLANK''@/$(HAVE_ISWBLANK)/g' \
+	      -e 's/@''HAVE_ISWCNTRL''@/$(HAVE_ISWCNTRL)/g' \
+	      -e 's/@''HAVE_WCTYPE_T''@/$(HAVE_WCTYPE_T)/g' \
+	      -e 's/@''HAVE_WCTRANS_T''@/$(HAVE_WCTRANS_T)/g' \
+	      -e 's/@''HAVE_WINT_T''@/$(HAVE_WINT_T)/g' \
+	      -e 's/@''REPLACE_ISWBLANK''@/$(REPLACE_ISWBLANK)/g' \
+	      -e 's/@''REPLACE_ISWCNTRL''@/$(REPLACE_ISWCNTRL)/g' \
+	      -e 's/@''REPLACE_TOWLOWER''@/$(REPLACE_TOWLOWER)/g' \
+	      -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
+	      -e '/definition of _GL_WARN_ON_USE/r $(WARN_ON_USE_H)' \
+	      < $(srcdir)/wctype.in.h; \
+	} > $@-t && \
+	mv $@-t $@
+MOSTLYCLEANFILES += wctype.h wctype.h-t
+
+endif
+EXTRA_DIST += wctype.in.h
+
+endif
+## end   gnulib module wctype-h
+
 ## begin gnulib module xalloc-oversized
 ifeq (,$(OMIT_GNULIB_MODULE_xalloc-oversized))
 
diff --git a/lib/hard-locale.c b/lib/hard-locale.c
new file mode 100644
index 0000000000..49bc6caff4
--- /dev/null
+++ b/lib/hard-locale.c
@@ -0,0 +1,72 @@
+/* hard-locale.c -- Determine whether a locale is hard.
+
+   Copyright (C) 1997-1999, 2002-2004, 2006-2007, 2009-2018 Free Software
+   Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+#include "hard-locale.h"
+
+#include <locale.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef __GLIBC__
+# define GLIBC_VERSION __GLIBC__
+#elif defined __UCLIBC__
+# define GLIBC_VERSION 2
+#else
+# define GLIBC_VERSION 0
+#endif
+
+/* Return true if the current CATEGORY locale is hard, i.e. if you
+   can't get away with assuming traditional C or POSIX behavior.  */
+bool
+hard_locale (int category)
+{
+  bool hard = true;
+  char const *p = setlocale (category, NULL);
+
+  if (p)
+    {
+      if (2 <= GLIBC_VERSION)
+        {
+          if (strcmp (p, "C") == 0 || strcmp (p, "POSIX") == 0)
+            hard = false;
+        }
+      else
+        {
+          char *locale = strdup (p);
+          if (locale)
+            {
+              /* Temporarily set the locale to the "C" and "POSIX" locales
+                 to find their names, so that we can determine whether one
+                 or the other is the caller's locale.  */
+              if (((p = setlocale (category, "C"))
+                   && strcmp (p, locale) == 0)
+                  || ((p = setlocale (category, "POSIX"))
+                      && strcmp (p, locale) == 0))
+                hard = false;
+
+              /* Restore the caller's locale.  */
+              setlocale (category, locale);
+              free (locale);
+            }
+        }
+    }
+
+  return hard;
+}
diff --git a/lib/hard-locale.h b/lib/hard-locale.h
new file mode 100644
index 0000000000..22eecc5ed8
--- /dev/null
+++ b/lib/hard-locale.h
@@ -0,0 +1,25 @@
+/* Determine whether a locale is hard.
+
+   Copyright (C) 1999, 2003-2004, 2009-2018 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#ifndef HARD_LOCALE_H_
+# define HARD_LOCALE_H_ 1
+
+# include <stdbool.h>
+
+bool hard_locale (int);
+
+#endif /* HARD_LOCALE_H_ */
diff --git a/lib/langinfo.in.h b/lib/langinfo.in.h
new file mode 100644
index 0000000000..96c237ae32
--- /dev/null
+++ b/lib/langinfo.in.h
@@ -0,0 +1,222 @@
+/* Substitute for and wrapper around <langinfo.h>.
+   Copyright (C) 2009-2018 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, see <https://www.gnu.org/licenses/>.  */
+
+/*
+ * POSIX <langinfo.h> for platforms that lack it or have an incomplete one.
+ * <http://www.opengroup.org/onlinepubs/9699919799/basedefs/langinfo.h.html>
+ */
+
+#ifndef _@GUARD_PREFIX@_LANGINFO_H
+
+#if __GNUC__ >= 3
+@PRAGMA_SYSTEM_HEADER@
+#endif
+@PRAGMA_COLUMNS@
+
+/* The include_next requires a split double-inclusion guard.  */
+#if @HAVE_LANGINFO_H@
+# @INCLUDE_NEXT@ @NEXT_LANGINFO_H@
+#endif
+
+#ifndef _@GUARD_PREFIX@_LANGINFO_H
+#define _@GUARD_PREFIX@_LANGINFO_H
+
+
+#if !@HAVE_LANGINFO_H@
+
+/* A platform that lacks <langinfo.h>.  */
+
+/* Assume that it also lacks <nl_types.h> and the nl_item type.  */
+# if !GNULIB_defined_nl_item
+typedef int nl_item;
+#  define GNULIB_defined_nl_item 1
+# endif
+
+/* nl_langinfo items of the LC_CTYPE category */
+# define CODESET     10000
+/* nl_langinfo items of the LC_NUMERIC category */
+# define RADIXCHAR   10001
+# define DECIMAL_POINT RADIXCHAR
+# define THOUSEP     10002
+# define THOUSANDS_SEP THOUSEP
+# define GROUPING    10114
+/* nl_langinfo items of the LC_TIME category */
+# define D_T_FMT     10003
+# define D_FMT       10004
+# define T_FMT       10005
+# define T_FMT_AMPM  10006
+# define AM_STR      10007
+# define PM_STR      10008
+# define DAY_1       10009
+# define DAY_2       (DAY_1 + 1)
+# define DAY_3       (DAY_1 + 2)
+# define DAY_4       (DAY_1 + 3)
+# define DAY_5       (DAY_1 + 4)
+# define DAY_6       (DAY_1 + 5)
+# define DAY_7       (DAY_1 + 6)
+# define ABDAY_1     10016
+# define ABDAY_2     (ABDAY_1 + 1)
+# define ABDAY_3     (ABDAY_1 + 2)
+# define ABDAY_4     (ABDAY_1 + 3)
+# define ABDAY_5     (ABDAY_1 + 4)
+# define ABDAY_6     (ABDAY_1 + 5)
+# define ABDAY_7     (ABDAY_1 + 6)
+# define MON_1       10023
+# define MON_2       (MON_1 + 1)
+# define MON_3       (MON_1 + 2)
+# define MON_4       (MON_1 + 3)
+# define MON_5       (MON_1 + 4)
+# define MON_6       (MON_1 + 5)
+# define MON_7       (MON_1 + 6)
+# define MON_8       (MON_1 + 7)
+# define MON_9       (MON_1 + 8)
+# define MON_10      (MON_1 + 9)
+# define MON_11      (MON_1 + 10)
+# define MON_12      (MON_1 + 11)
+# define ALTMON_1    10200
+# define ALTMON_2    (ALTMON_1 + 1)
+# define ALTMON_3    (ALTMON_1 + 2)
+# define ALTMON_4    (ALTMON_1 + 3)
+# define ALTMON_5    (ALTMON_1 + 4)
+# define ALTMON_6    (ALTMON_1 + 5)
+# define ALTMON_7    (ALTMON_1 + 6)
+# define ALTMON_8    (ALTMON_1 + 7)
+# define ALTMON_9    (ALTMON_1 + 8)
+# define ALTMON_10   (ALTMON_1 + 9)
+# define ALTMON_11   (ALTMON_1 + 10)
+# define ALTMON_12   (ALTMON_1 + 11)
+# define ABMON_1     10035
+# define ABMON_2     (ABMON_1 + 1)
+# define ABMON_3     (ABMON_1 + 2)
+# define ABMON_4     (ABMON_1 + 3)
+# define ABMON_5     (ABMON_1 + 4)
+# define ABMON_6     (ABMON_1 + 5)
+# define ABMON_7     (ABMON_1 + 6)
+# define ABMON_8     (ABMON_1 + 7)
+# define ABMON_9     (ABMON_1 + 8)
+# define ABMON_10    (ABMON_1 + 9)
+# define ABMON_11    (ABMON_1 + 10)
+# define ABMON_12    (ABMON_1 + 11)
+# define ERA         10047
+# define ERA_D_FMT   10048
+# define ERA_D_T_FMT 10049
+# define ERA_T_FMT   10050
+# define ALT_DIGITS  10051
+/* nl_langinfo items of the LC_MONETARY category */
+# define CRNCYSTR    10052
+# define CURRENCY_SYMBOL   CRNCYSTR
+# define INT_CURR_SYMBOL   10100
+# define MON_DECIMAL_POINT 10101
+# define MON_THOUSANDS_SEP 10102
+# define MON_GROUPING      10103
+# define POSITIVE_SIGN     10104
+# define NEGATIVE_SIGN     10105
+# define FRAC_DIGITS       10106
+# define INT_FRAC_DIGITS   10107
+# define P_CS_PRECEDES     10108
+# define N_CS_PRECEDES     10109
+# define P_SEP_BY_SPACE    10110
+# define N_SEP_BY_SPACE    10111
+# define P_SIGN_POSN       10112
+# define N_SIGN_POSN       10113
+/* nl_langinfo items of the LC_MESSAGES category */
+# define YESEXPR     10053
+# define NOEXPR      10054
+
+#else
+
+/* A platform that has <langinfo.h>.  */
+
+# if !@HAVE_LANGINFO_CODESET@
+#  define CODESET     10000
+#  define GNULIB_defined_CODESET 1
+# endif
+
+# if !@HAVE_LANGINFO_T_FMT_AMPM@
+#  define T_FMT_AMPM  10006
+#  define GNULIB_defined_T_FMT_AMPM 1
+# endif
+
+# if !@HAVE_LANGINFO_ALTMON@
+#  define ALTMON_1    10200
+#  define ALTMON_2    (ALTMON_1 + 1)
+#  define ALTMON_3    (ALTMON_1 + 2)
+#  define ALTMON_4    (ALTMON_1 + 3)
+#  define ALTMON_5    (ALTMON_1 + 4)
+#  define ALTMON_6    (ALTMON_1 + 5)
+#  define ALTMON_7    (ALTMON_1 + 6)
+#  define ALTMON_8    (ALTMON_1 + 7)
+#  define ALTMON_9    (ALTMON_1 + 8)
+#  define ALTMON_10   (ALTMON_1 + 9)
+#  define ALTMON_11   (ALTMON_1 + 10)
+#  define ALTMON_12   (ALTMON_1 + 11)
+#  define GNULIB_defined_ALTMON 1
+# endif
+
+# if !@HAVE_LANGINFO_ERA@
+#  define ERA         10047
+#  define ERA_D_FMT   10048
+#  define ERA_D_T_FMT 10049
+#  define ERA_T_FMT   10050
+#  define ALT_DIGITS  10051
+#  define GNULIB_defined_ERA 1
+# endif
+
+# if !@HAVE_LANGINFO_YESEXPR@
+#  define YESEXPR     10053
+#  define NOEXPR      10054
+#  define GNULIB_defined_YESEXPR 1
+# endif
+
+#endif
+
+/* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
+
+/* The definition of _GL_WARN_ON_USE is copied here.  */
+
+/* Declare overridden functions.  */
+
+
+/* Return a piece of locale dependent information.
+   Note: The difference between nl_langinfo (CODESET) and locale_charset ()
+   is that the latter normalizes the encoding names to GNU conventions.  */
+
+#if @GNULIB_NL_LANGINFO@
+# if @REPLACE_NL_LANGINFO@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef nl_langinfo
+#   define nl_langinfo rpl_nl_langinfo
+#  endif
+_GL_FUNCDECL_RPL (nl_langinfo, char *, (nl_item item));
+_GL_CXXALIAS_RPL (nl_langinfo, char *, (nl_item item));
+# else
+#  if !@HAVE_NL_LANGINFO@
+_GL_FUNCDECL_SYS (nl_langinfo, char *, (nl_item item));
+#  endif
+_GL_CXXALIAS_SYS (nl_langinfo, char *, (nl_item item));
+# endif
+_GL_CXXALIASWARN (nl_langinfo);
+#elif defined GNULIB_POSIXCHECK
+# undef nl_langinfo
+# if HAVE_RAW_DECL_NL_LANGINFO
+_GL_WARN_ON_USE (nl_langinfo, "nl_langinfo is not portable - "
+                 "use gnulib module nl_langinfo for portability");
+# endif
+#endif
+
+
+#endif /* _@GUARD_PREFIX@_LANGINFO_H */
+#endif /* _@GUARD_PREFIX@_LANGINFO_H */
diff --git a/lib/localcharset.c b/lib/localcharset.c
new file mode 100644
index 0000000000..58c5718c3e
--- /dev/null
+++ b/lib/localcharset.c
@@ -0,0 +1,996 @@
+/* Determine a canonical name for the current locale's character encoding.
+
+   Copyright (C) 2000-2006, 2008-2018 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along
+   with this program; if not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <[email-masked]>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include "localcharset.h"
+
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#if defined __APPLE__ && defined __MACH__ && HAVE_LANGINFO_CODESET
+# define DARWIN7 /* Darwin 7 or newer, i.e. Mac OS X 10.3 or newer */
+#endif
+
+#if defined _WIN32 && !defined __CYGWIN__
+# define WINDOWS_NATIVE
+# include <locale.h>
+#endif
+
+#if defined __EMX__
+/* Assume EMX program runs on OS/2, even if compiled under DOS.  */
+# ifndef OS2
+#  define OS2
+# endif
+#endif
+
+#if !defined WINDOWS_NATIVE
+# if HAVE_LANGINFO_CODESET
+#  include <langinfo.h>
+# else
+#  if 0 /* see comment regarding use of setlocale(), below */
+#   include <locale.h>
+#  endif
+# endif
+# ifdef __CYGWIN__
+#  define WIN32_LEAN_AND_MEAN
+#  include <windows.h>
+# endif
+#elif defined WINDOWS_NATIVE
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+#endif
+#if defined OS2
+# define INCL_DOS
+# include <os2.h>
+#endif
+
+/* For MB_CUR_MAX_L */
+#if defined DARWIN7
+# include <xlocale.h>
+#endif
+
+
+#if HAVE_LANGINFO_CODESET || defined WINDOWS_NATIVE || defined OS2
+
+/* On these platforms, we use a mapping from non-canonical encoding name
+   to GNU canonical encoding name.  */
+
+/* With glibc-2.1 or newer, we don't need any canonicalization,
+   because glibc has iconv and both glibc and libiconv support all
+   GNU canonical names directly.  */
+# if !((defined __GNU_LIBRARY__ && __GLIBC__ >= 2) || defined __UCLIBC__)
+
+struct table_entry
+{
+  const char alias[11+1];
+  const char canonical[11+1];
+};
+
+/* Table of platform-dependent mappings, sorted in ascending order.  */
+static const struct table_entry alias_table[] =
+  {
+#  if defined __FreeBSD__                                   /* FreeBSD */
+  /*{ "ARMSCII-8",  "ARMSCII-8" },*/
+    { "Big5",       "BIG5" },
+    { "C",          "ASCII" },
+  /*{ "CP1131",     "CP1131" },*/
+  /*{ "CP1251",     "CP1251" },*/
+  /*{ "CP866",      "CP866" },*/
+  /*{ "GB18030",    "GB18030" },*/
+  /*{ "GB2312",     "GB2312" },*/
+  /*{ "GBK",        "GBK" },*/
+  /*{ "ISCII-DEV",  "?" },*/
+    { "ISO8859-1",  "ISO-8859-1" },
+    { "ISO8859-13", "ISO-8859-13" },
+    { "ISO8859-15", "ISO-8859-15" },
+    { "ISO8859-2",  "ISO-8859-2" },
+    { "ISO8859-5",  "ISO-8859-5" },
+    { "ISO8859-7",  "ISO-8859-7" },
+    { "ISO8859-9",  "ISO-8859-9" },
+  /*{ "KOI8-R",     "KOI8-R" },*/
+  /*{ "KOI8-U",     "KOI8-U" },*/
+    { "SJIS",       "SHIFT_JIS" },
+    { "US-ASCII",   "ASCII" },
+    { "eucCN",      "GB2312" },
+    { "eucJP",      "EUC-JP" },
+    { "eucKR",      "EUC-KR" }
+#   define alias_table_defined
+#  endif
+#  if defined __NetBSD__                                    /* NetBSD */
+    { "646",        "ASCII" },
+  /*{ "ARMSCII-8",  "ARMSCII-8" },*/
+  /*{ "BIG5",       "BIG5" },*/
+    { "Big5-HKSCS", "BIG5-HKSCS" },
+  /*{ "CP1251",     "CP1251" },*/
+  /*{ "CP866",      "CP866" },*/
+  /*{ "GB18030",    "GB18030" },*/
+  /*{ "GB2312",     "GB2312" },*/
+    { "ISO8859-1",  "ISO-8859-1" },
+    { "ISO8859-13", "ISO-8859-13" },
+    { "ISO8859-15", "ISO-8859-15" },
+    { "ISO8859-2",  "ISO-8859-2" },
+    { "ISO8859-4",  "ISO-8859-4" },
+    { "ISO8859-5",  "ISO-8859-5" },
+    { "ISO8859-7",  "ISO-8859-7" },
+  /*{ "KOI8-R",     "KOI8-R" },*/
+  /*{ "KOI8-U",     "KOI8-U" },*/
+  /*{ "PT154",      "PT154" },*/
+    { "SJIS",       "SHIFT_JIS" },
+    { "eucCN",      "GB2312" },
+    { "eucJP",      "EUC-JP" },
+    { "eucKR",      "EUC-KR" },
+    { "eucTW",      "EUC-TW" }
+#   define alias_table_defined
+#  endif
+#  if defined __OpenBSD__                                   /* OpenBSD */
+    { "646",        "ASCII" },
+    { "ISO8859-1",  "ISO-8859-1" },
+    { "ISO8859-13", "ISO-8859-13" },
+    { "ISO8859-15", "ISO-8859-15" },
+    { "ISO8859-2",  "ISO-8859-2" },
+    { "ISO8859-4",  "ISO-8859-4" },
+    { "ISO8859-5",  "ISO-8859-5" },
+    { "ISO8859-7",  "ISO-8859-7" }
+#   define alias_table_defined
+#  endif
+#  if defined __APPLE__ && defined __MACH__                 /* Mac OS X */
+    /* Darwin 7.5 has nl_langinfo(CODESET), but sometimes its value is
+       useless:
+       - It returns the empty string when LANG is set to a locale of the
+         form ll_CC, although ll_CC/LC_CTYPE is a symlink to an UTF-8
+         LC_CTYPE file.
+       - The environment variables LANG, LC_CTYPE, LC_ALL are not set by
+         the system; nl_langinfo(CODESET) returns "US-ASCII" in this case.
+       - The documentation says:
+           "... all code that calls BSD system routines should ensure
+            that the const *char parameters of these routines are in UTF-8
+            encoding. All BSD system functions expect their string
+            parameters to be in UTF-8 encoding and nothing else."
+         It also says
+           "An additional caveat is that string parameters for files,
+            paths, and other file-system entities must be in canonical
+            UTF-8. In a canonical UTF-8 Unicode string, all decomposable
+            characters are decomposed ..."
+         but this is not true: You can pass non-decomposed UTF-8 strings
+         to file system functions, and it is the OS which will convert
+         them to decomposed UTF-8 before accessing the file system.
+       - The Apple Terminal application displays UTF-8 by default.
+       - However, other applications are free to use different encodings:
+         - xterm uses ISO-8859-1 by default.
+         - TextEdit uses MacRoman by default.
+       We prefer UTF-8 over decomposed UTF-8-MAC because one should
+       minimize the use of decomposed Unicode. Unfortunately, through the
+       Darwin file system, decomposed UTF-8 strings are leaked into user
+       space nevertheless.
+       Then there are also the locales with encodings other than US-ASCII
+       and UTF-8. These locales can be occasionally useful to users (e.g.
+       when grepping through ISO-8859-1 encoded text files), when all their
+       file names are in US-ASCII.
+     */
+    { "ARMSCII-8",  "ARMSCII-8" },
+    { "Big5",       "BIG5" },
+    { "Big5HKSCS",  "BIG5-HKSCS" },
+    { "CP1131",     "CP1131" },
+    { "CP1251",     "CP1251" },
+    { "CP866",      "CP866" },
+    { "CP949",      "CP949" },
+    { "GB18030",    "GB18030" },
+    { "GB2312",     "GB2312" },
+    { "GBK",        "GBK" },
+  /*{ "ISCII-DEV",  "?" },*/
+    { "ISO8859-1",  "ISO-8859-1" },
+    { "ISO8859-13", "ISO-8859-13" },
+    { "ISO8859-15", "ISO-8859-15" },
+    { "ISO8859-2",  "ISO-8859-2" },
+    { "ISO8859-4",  "ISO-8859-4" },
+    { "ISO8859-5",  "ISO-8859-5" },
+    { "ISO8859-7",  "ISO-8859-7" },
+    { "ISO8859-9",  "ISO-8859-9" },
+    { "KOI8-R",     "KOI8-R" },
+    { "KOI8-U",     "KOI8-U" },
+    { "PT154",      "PT154" },
+    { "SJIS",       "SHIFT_JIS" },
+    { "eucCN",      "GB2312" },
+    { "eucJP",      "EUC-JP" },
+    { "eucKR",      "EUC-KR" }
+#   define alias_table_defined
+#  endif
+#  if defined _AIX                                          /* AIX */
+  /*{ "GBK",        "GBK" },*/
+    { "IBM-1046",   "CP1046" },
+    { "IBM-1124",   "CP1124" },
+    { "IBM-1129",   "CP1129" },
+    { "IBM-1252",   "CP1252" },
+    { "IBM-850",    "CP850" },
+    { "IBM-856",    "CP856" },
+    { "IBM-921",    "ISO-8859-13" },
+    { "IBM-922",    "CP922" },
+    { "IBM-932",    "CP932" },
+    { "IBM-943",    "CP943" },
+    { "IBM-eucCN",  "GB2312" },
+    { "IBM-eucJP",  "EUC-JP" },
+    { "IBM-eucKR",  "EUC-KR" },
+    { "IBM-eucTW",  "EUC-TW" },
+    { "ISO8859-1",  "ISO-8859-1" },
+    { "ISO8859-15", "ISO-8859-15" },
+    { "ISO8859-2",  "ISO-8859-2" },
+    { "ISO8859-5",  "ISO-8859-5" },
+    { "ISO8859-6",  "ISO-8859-6" },
+    { "ISO8859-7",  "ISO-8859-7" },
+    { "ISO8859-8",  "ISO-8859-8" },
+    { "ISO8859-9",  "ISO-8859-9" },
+    { "TIS-620",    "TIS-620" },
+  /*{ "UTF-8",      "UTF-8" },*/
+    { "big5",       "BIG5" }
+#   define alias_table_defined
+#  endif
+#  if defined __hpux                                        /* HP-UX */
+    { "SJIS",      "SHIFT_JIS" },
+    { "arabic8",   "HP-ARABIC8" },
+    { "big5",      "BIG5" },
+    { "cp1251",    "CP1251" },
+    { "eucJP",     "EUC-JP" },
+    { "eucKR",     "EUC-KR" },
+    { "eucTW",     "EUC-TW" },
+    { "gb18030",   "GB18030" },
+    { "greek8",    "HP-GREEK8" },
+    { "hebrew8",   "HP-HEBREW8" },
+    { "hkbig5",    "BIG5-HKSCS" },
+    { "hp15CN",    "GB2312" },
+    { "iso88591",  "ISO-8859-1" },
+    { "iso885913", "ISO-8859-13" },
+    { "iso885915", "ISO-8859-15" },
+    { "iso88592",  "ISO-8859-2" },
+    { "iso88594",  "ISO-8859-4" },
+    { "iso88595",  "ISO-8859-5" },
+    { "iso88596",  "ISO-8859-6" },
+    { "iso88597",  "ISO-8859-7" },
+    { "iso88598",  "ISO-8859-8" },
+    { "iso88599",  "ISO-8859-9" },
+    { "kana8",     "HP-KANA8" },
+    { "koi8r",     "KOI8-R" },
+    { "roman8",    "HP-ROMAN8" },
+    { "tis620",    "TIS-620" },
+    { "turkish8",  "HP-TURKISH8" },
+    { "utf8",      "UTF-8" }
+#   define alias_table_defined
+#  endif
+#  if defined __sgi                                         /* IRIX */
+    { "ISO8859-1",  "ISO-8859-1" },
+    { "ISO8859-15", "ISO-8859-15" },
+    { "ISO8859-2",  "ISO-8859-2" },
+    { "ISO8859-5",  "ISO-8859-5" },
+    { "ISO8859-7",  "ISO-8859-7" },
+    { "ISO8859-9",  "ISO-8859-9" },
+    { "eucCN",      "GB2312" },
+    { "eucJP",      "EUC-JP" },
+    { "eucKR",      "EUC-KR" },
+    { "eucTW",      "EUC-TW" }
+#   define alias_table_defined
+#  endif
+#  if defined __osf__                                       /* OSF/1 */
+  /*{ "GBK",        "GBK" },*/
+    { "ISO8859-1",  "ISO-8859-1" },
+    { "ISO8859-15", "ISO-8859-15" },
+    { "ISO8859-2",  "ISO-8859-2" },
+    { "ISO8859-4",  "ISO-8859-4" },
+    { "ISO8859-5",  "ISO-8859-5" },
+    { "ISO8859-7",  "ISO-8859-7" },
+    { "ISO8859-8",  "ISO-8859-8" },
+    { "ISO8859-9",  "ISO-8859-9" },
+    { "KSC5601",    "CP949" },
+    { "SJIS",       "SHIFT_JIS" },
+    { "TACTIS",     "TIS-620" },
+  /*{ "UTF-8",      "UTF-8" },*/
+    { "big5",       "BIG5" },
+    { "cp850",      "CP850" },
+    { "dechanyu",   "DEC-HANYU" },
+    { "dechanzi",   "GB2312" },
+    { "deckanji",   "DEC-KANJI" },
+    { "deckorean",  "EUC-KR" },
+    { "eucJP",      "EUC-JP" },
+    { "eucKR",      "EUC-KR" },
+    { "eucTW",      "EUC-TW" },
+    { "sdeckanji",  "EUC-JP" }
+#   define alias_table_defined
+#  endif
+#  if defined __sun                                         /* Solaris */
+    { "5601",        "EUC-KR" },
+    { "646",         "ASCII" },
+  /*{ "BIG5",        "BIG5" },*/
+    { "Big5-HKSCS",  "BIG5-HKSCS" },
+    { "GB18030",     "GB18030" },
+  /*{ "GBK",         "GBK" },*/
+    { "ISO8859-1",   "ISO-8859-1" },
+    { "ISO8859-11",  "TIS-620" },
+    { "ISO8859-13",  "ISO-8859-13" },
+    { "ISO8859-15",  "ISO-8859-15" },
+    { "ISO8859-2",   "ISO-8859-2" },
+    { "ISO8859-3",   "ISO-8859-3" },
+    { "ISO8859-4",   "ISO-8859-4" },
+    { "ISO8859-5",   "ISO-8859-5" },
+    { "ISO8859-6",   "ISO-8859-6" },
+    { "ISO8859-7",   "ISO-8859-7" },
+    { "ISO8859-8",   "ISO-8859-8" },
+    { "ISO8859-9",   "ISO-8859-9" },
+    { "PCK",         "SHIFT_JIS" },
+    { "TIS620.2533", "TIS-620" },
+  /*{ "UTF-8",       "UTF-8" },*/
+    { "ansi-1251",   "CP1251" },
+    { "cns11643",    "EUC-TW" },
+    { "eucJP",       "EUC-JP" },
+    { "gb2312",      "GB2312" },
+    { "koi8-r",      "KOI8-R" }
+#   define alias_table_defined
+#  endif
+#  if defined __minix                                       /* Minix */
+    { "646", "ASCII" }
+#   define alias_table_defined
+#  endif
+#  if defined WINDOWS_NATIVE || defined __CYGWIN__          /* Windows */
+    { "CP1361",  "JOHAB" },
+    { "CP20127", "ASCII" },
+    { "CP20866", "KOI8-R" },
+    { "CP20936", "GB2312" },
+    { "CP21866", "KOI8-RU" },
+    { "CP28591", "ISO-8859-1" },
+    { "CP28592", "ISO-8859-2" },
+    { "CP28593", "ISO-8859-3" },
+    { "CP28594", "ISO-8859-4" },
+    { "CP28595", "ISO-8859-5" },
+    { "CP28596", "ISO-8859-6" },
+    { "CP28597", "ISO-8859-7" },
+    { "CP28598", "ISO-8859-8" },
+    { "CP28599", "ISO-8859-9" },
+    { "CP28605", "ISO-8859-15" },
+    { "CP38598", "ISO-8859-8" },
+    { "CP51932", "EUC-JP" },
+    { "CP51936", "GB2312" },
+    { "CP51949", "EUC-KR" },
+    { "CP51950", "EUC-TW" },
+    { "CP54936", "GB18030" },
+    { "CP65001", "UTF-8" },
+    { "CP936",   "GBK" }
+#   define alias_table_defined
+#  endif
+#  if defined OS2                                           /* OS/2 */
+    /* The list of encodings is taken from "List of OS/2 Codepages"
+       by Alex Taylor:
+       <http://altsan.org/os2/toolkits/uls/index.html#codepages>.
+       See also "IBM Globalization - Code page identifiers":
+       <https://www-01.ibm.com/software/globalization/cp/cp_cpgid.html>.  */
+    { "CP1089", "ISO-8859-6" },
+    { "CP1208", "UTF-8" },
+    { "CP1381", "GB2312" },
+    { "CP1386", "GBK" },
+    { "CP3372", "EUC-JP" },
+    { "CP813",  "ISO-8859-7" },
+    { "CP819",  "ISO-8859-1" },
+    { "CP878",  "KOI8-R" },
+    { "CP912",  "ISO-8859-2" },
+    { "CP913",  "ISO-8859-3" },
+    { "CP914",  "ISO-8859-4" },
+    { "CP915",  "ISO-8859-5" },
+    { "CP916",  "ISO-8859-8" },
+    { "CP920",  "ISO-8859-9" },
+    { "CP921",  "ISO-8859-13" },
+    { "CP923",  "ISO-8859-15" },
+    { "CP954",  "EUC-JP" },
+    { "CP964",  "EUC-TW" },
+    { "CP970",  "EUC-KR" }
+#   define alias_table_defined
+#  endif
+#  if defined VMS                                           /* OpenVMS */
+    /* The list of encodings is taken from the OpenVMS 7.3-1 documentation
+       "Compaq C Run-Time Library Reference Manual for OpenVMS systems"
+       section 10.7 "Handling Different Character Sets".  */
+    { "DECHANYU",  "DEC-HANYU" },
+    { "DECHANZI",  "GB2312" },
+    { "DECKANJI",  "DEC-KANJI" },
+    { "DECKOREAN", "EUC-KR" },
+    { "ISO8859-1", "ISO-8859-1" },
+    { "ISO8859-2", "ISO-8859-2" },
+    { "ISO8859-5", "ISO-8859-5" },
+    { "ISO8859-7", "ISO-8859-7" },
+    { "ISO8859-8", "ISO-8859-8" },
+    { "ISO8859-9", "ISO-8859-9" },
+    { "SDECKANJI", "EUC-JP" },
+    { "SJIS",      "SHIFT_JIS" },
+    { "eucJP",     "EUC-JP" },
+    { "eucTW",     "EUC-TW" }
+#   define alias_table_defined
+#  endif
+#  ifndef alias_table_defined
+    /* Just a dummy entry, to avoid a C syntax error.  */
+    { "", "" }
+#  endif
+  };
+
+# endif
+
+#else
+
+/* On these platforms, we use a mapping from locale name to GNU canonical
+   encoding name.  */
+
+struct table_entry
+{
+  const char locale[17+1];
+  const char canonical[11+1];
+};
+
+/* Table of platform-dependent mappings, sorted in ascending order.  */
+static const struct table_entry locale_table[] =
+  {
+# if defined __FreeBSD__                                    /* FreeBSD 4.2 */
+    { "cs_CZ.ISO_8859-2",  "ISO-8859-2" },
+    { "da_DK.DIS_8859-15", "ISO-8859-15" },
+    { "da_DK.ISO_8859-1",  "ISO-8859-1" },
+    { "de_AT.DIS_8859-15", "ISO-8859-15" },
+    { "de_AT.ISO_8859-1",  "ISO-8859-1" },
+    { "de_CH.DIS_8859-15", "ISO-8859-15" },
+    { "de_CH.ISO_8859-1",  "ISO-8859-1" },
+    { "de_DE.DIS_8859-15", "ISO-8859-15" },
+    { "de_DE.ISO_8859-1",  "ISO-8859-1" },
+    { "en_AU.DIS_8859-15", "ISO-8859-15" },
+    { "en_AU.ISO_8859-1",  "ISO-8859-1" },
+    { "en_CA.DIS_8859-15", "ISO-8859-15" },
+    { "en_CA.ISO_8859-1",  "ISO-8859-1" },
+    { "en_GB.DIS_8859-15", "ISO-8859-15" },
+    { "en_GB.ISO_8859-1",  "ISO-8859-1" },
+    { "en_US.DIS_8859-15", "ISO-8859-15" },
+    { "en_US.ISO_8859-1",  "ISO-8859-1" },
+    { "es_ES.DIS_8859-15", "ISO-8859-15" },
+    { "es_ES.ISO_8859-1",  "ISO-8859-1" },
+    { "fi_FI.DIS_8859-15", "ISO-8859-15" },
+    { "fi_FI.ISO_8859-1",  "ISO-8859-1" },
+    { "fr_BE.DIS_8859-15", "ISO-8859-15" },
+    { "fr_BE.ISO_8859-1",  "ISO-8859-1" },
+    { "fr_CA.DIS_8859-15", "ISO-8859-15" },
+    { "fr_CA.ISO_8859-1",  "ISO-8859-1" },
+    { "fr_CH.DIS_8859-15", "ISO-8859-15" },
+    { "fr_CH.ISO_8859-1",  "ISO-8859-1" },
+    { "fr_FR.DIS_8859-15", "ISO-8859-15" },
+    { "fr_FR.ISO_8859-1",  "ISO-8859-1" },
+    { "hr_HR.ISO_8859-2",  "ISO-8859-2" },
+    { "hu_HU.ISO_8859-2",  "ISO-8859-2" },
+    { "is_IS.DIS_8859-15", "ISO-8859-15" },
+    { "is_IS.ISO_8859-1",  "ISO-8859-1" },
+    { "it_CH.DIS_8859-15", "ISO-8859-15" },
+    { "it_CH.ISO_8859-1",  "ISO-8859-1" },
+    { "it_IT.DIS_8859-15", "ISO-8859-15" },
+    { "it_IT.ISO_8859-1",  "ISO-8859-1" },
+    { "ja_JP.EUC",         "EUC-JP" },
+    { "ja_JP.SJIS",        "SHIFT_JIS" },
+    { "ja_JP.Shift_JIS",   "SHIFT_JIS" },
+    { "ko_KR.EUC",         "EUC-KR" },
+    { "la_LN.ASCII",       "ASCII" },
+    { "la_LN.DIS_8859-15", "ISO-8859-15" },
+    { "la_LN.ISO_8859-1",  "ISO-8859-1" },
+    { "la_LN.ISO_8859-2",  "ISO-8859-2" },
+    { "la_LN.ISO_8859-4",  "ISO-8859-4" },
+    { "lt_LN.ASCII",       "ASCII" },
+    { "lt_LN.DIS_8859-15", "ISO-8859-15" },
+    { "lt_LN.ISO_8859-1",  "ISO-8859-1" },
+    { "lt_LN.ISO_8859-2",  "ISO-8859-2" },
+    { "lt_LT.ISO_8859-4",  "ISO-8859-4" },
+    { "nl_BE.DIS_8859-15", "ISO-8859-15" },
+    { "nl_BE.ISO_8859-1",  "ISO-8859-1" },
+    { "nl_NL.DIS_8859-15", "ISO-8859-15" },
+    { "nl_NL.ISO_8859-1",  "ISO-8859-1" },
+    { "no_NO.DIS_8859-15", "ISO-8859-15" },
+    { "no_NO.ISO_8859-1",  "ISO-8859-1" },
+    { "pl_PL.ISO_8859-2",  "ISO-8859-2" },
+    { "pt_PT.DIS_8859-15", "ISO-8859-15" },
+    { "pt_PT.ISO_8859-1",  "ISO-8859-1" },
+    { "ru_RU.CP866",       "CP866" },
+    { "ru_RU.ISO_8859-5",  "ISO-8859-5" },
+    { "ru_RU.KOI8-R",      "KOI8-R" },
+    { "ru_SU.CP866",       "CP866" },
+    { "ru_SU.ISO_8859-5",  "ISO-8859-5" },
+    { "ru_SU.KOI8-R",      "KOI8-R" },
+    { "sl_SI.ISO_8859-2",  "ISO-8859-2" },
+    { "sv_SE.DIS_8859-15", "ISO-8859-15" },
+    { "sv_SE.ISO_8859-1",  "ISO-8859-1" },
+    { "uk_UA.KOI8-U",      "KOI8-U" },
+    { "zh_CN.EUC",         "GB2312" },
+    { "zh_TW.BIG5",        "BIG5" },
+    { "zh_TW.Big5",        "BIG5" }
+#  define locale_table_defined
+# endif
+# if defined __DJGPP__                                      /* DOS / DJGPP 2.03 */
+    /* The encodings given here may not all be correct.
+       If you find that the encoding given for your language and
+       country is not the one your DOS machine actually uses, just
+       correct it in this file, and send a mail to
+       Juan Manuel Guerrero <[email-masked]>
+       and <[email-masked]>.  */
+    { "C",     "ASCII" },
+    { "ar",    "CP864" },
+    { "ar_AE", "CP864" },
+    { "ar_DZ", "CP864" },
+    { "ar_EG", "CP864" },
+    { "ar_IQ", "CP864" },
+    { "ar_IR", "CP864" },
+    { "ar_JO", "CP864" },
+    { "ar_KW", "CP864" },
+    { "ar_MA", "CP864" },
+    { "ar_OM", "CP864" },
+    { "ar_QA", "CP864" },
+    { "ar_SA", "CP864" },
+    { "ar_SY", "CP864" },
+    { "be",    "CP866" },
+    { "be_BE", "CP866" },
+    { "bg",    "CP866" }, /* not CP855 ?? */
+    { "bg_BG", "CP866" }, /* not CP855 ?? */
+    { "ca",    "CP850" },
+    { "ca_ES", "CP850" },
+    { "cs",    "CP852" },
+    { "cs_CZ", "CP852" },
+    { "da",    "CP865" }, /* not CP850 ?? */
+    { "da_DK", "CP865" }, /* not CP850 ?? */
+    { "de",    "CP850" },
+    { "de_AT", "CP850" },
+    { "de_CH", "CP850" },
+    { "de_DE", "CP850" },
+    { "el",    "CP869" },
+    { "el_GR", "CP869" },
+    { "en",    "CP850" },
+    { "en_AU", "CP850" }, /* not CP437 ?? */
+    { "en_CA", "CP850" },
+    { "en_GB", "CP850" },
+    { "en_NZ", "CP437" },
+    { "en_US", "CP437" },
+    { "en_ZA", "CP850" }, /* not CP437 ?? */
+    { "eo",    "CP850" },
+    { "eo_EO", "CP850" },
+    { "es",    "CP850" },
+    { "es_AR", "CP850" },
+    { "es_BO", "CP850" },
+    { "es_CL", "CP850" },
+    { "es_CO", "CP850" },
+    { "es_CR", "CP850" },
+    { "es_CU", "CP850" },
+    { "es_DO", "CP850" },
+    { "es_EC", "CP850" },
+    { "es_ES", "CP850" },
+    { "es_GT", "CP850" },
+    { "es_HN", "CP850" },
+    { "es_MX", "CP850" },
+    { "es_NI", "CP850" },
+    { "es_PA", "CP850" },
+    { "es_PE", "CP850" },
+    { "es_PY", "CP850" },
+    { "es_SV", "CP850" },
+    { "es_UY", "CP850" },
+    { "es_VE", "CP850" },
+    { "et",    "CP850" },
+    { "et_EE", "CP850" },
+    { "eu",    "CP850" },
+    { "eu_ES", "CP850" },
+    { "fi",    "CP850" },
+    { "fi_FI", "CP850" },
+    { "fr",    "CP850" },
+    { "fr_BE", "CP850" },
+    { "fr_CA", "CP850" },
+    { "fr_CH", "CP850" },
+    { "fr_FR", "CP850" },
+    { "ga",    "CP850" },
+    { "ga_IE", "CP850" },
+    { "gd",    "CP850" },
+    { "gd_GB", "CP850" },
+    { "gl",    "CP850" },
+    { "gl_ES", "CP850" },
+    { "he",    "CP862" },
+    { "he_IL", "CP862" },
+    { "hr",    "CP852" },
+    { "hr_HR", "CP852" },
+    { "hu",    "CP852" },
+    { "hu_HU", "CP852" },
+    { "id",    "CP850" }, /* not CP437 ?? */
+    { "id_ID", "CP850" }, /* not CP437 ?? */
+    { "is",    "CP861" }, /* not CP850 ?? */
+    { "is_IS", "CP861" }, /* not CP850 ?? */
+    { "it",    "CP850" },
+    { "it_CH", "CP850" },
+    { "it_IT", "CP850" },
+    { "ja",    "CP932" },
+    { "ja_JP", "CP932" },
+    { "kr",    "CP949" }, /* not CP934 ?? */
+    { "kr_KR", "CP949" }, /* not CP934 ?? */
+    { "lt",    "CP775" },
+    { "lt_LT", "CP775" },
+    { "lv",    "CP775" },
+    { "lv_LV", "CP775" },
+    { "mk",    "CP866" }, /* not CP855 ?? */
+    { "mk_MK", "CP866" }, /* not CP855 ?? */
+    { "mt",    "CP850" },
+    { "mt_MT", "CP850" },
+    { "nb",    "CP865" }, /* not CP850 ?? */
+    { "nb_NO", "CP865" }, /* not CP850 ?? */
+    { "nl",    "CP850" },
+    { "nl_BE", "CP850" },
+    { "nl_NL", "CP850" },
+    { "nn",    "CP865" }, /* not CP850 ?? */
+    { "nn_NO", "CP865" }, /* not CP850 ?? */
+    { "no",    "CP865" }, /* not CP850 ?? */
+    { "no_NO", "CP865" }, /* not CP850 ?? */
+    { "pl",    "CP852" },
+    { "pl_PL", "CP852" },
+    { "pt",    "CP850" },
+    { "pt_BR", "CP850" },
+    { "pt_PT", "CP850" },
+    { "ro",    "CP852" },
+    { "ro_RO", "CP852" },
+    { "ru",    "CP866" },
+    { "ru_RU", "CP866" },
+    { "sk",    "CP852" },
+    { "sk_SK", "CP852" },
+    { "sl",    "CP852" },
+    { "sl_SI", "CP852" },
+    { "sq",    "CP852" },
+    { "sq_AL", "CP852" },
+    { "sr",    "CP852" }, /* CP852 or CP866 or CP855 ?? */
+    { "sr_CS", "CP852" }, /* CP852 or CP866 or CP855 ?? */
+    { "sr_YU", "CP852" }, /* CP852 or CP866 or CP855 ?? */
+    { "sv",    "CP850" },
+    { "sv_SE", "CP850" },
+    { "th",    "CP874" },
+    { "th_TH", "CP874" },
+    { "tr",    "CP857" },
+    { "tr_TR", "CP857" },
+    { "uk",    "CP1125" },
+    { "uk_UA", "CP1125" },
+    { "zh_CN", "GBK" },
+    { "zh_TW", "CP950" } /* not CP938 ?? */
+#  define locale_table_defined
+# endif
+# ifndef locale_table_defined
+    /* Just a dummy entry, to avoid a C syntax error.  */
+    { "", "" }
+# endif
+  };
+
+#endif
+
+
+/* Determine the current locale's character encoding, and canonicalize it
+   into one of the canonical names listed in localcharset.h.
+   The result must not be freed; it is statically allocated.
+   If the canonical name cannot be determined, the result is a non-canonical
+   name.  */
+
+#ifdef STATIC
+STATIC
+#endif
+const char *
+locale_charset (void)
+{
+  const char *codeset;
+
+#if HAVE_LANGINFO_CODESET || defined WINDOWS_NATIVE || defined OS2
+
+# if HAVE_LANGINFO_CODESET
+
+  /* Most systems support nl_langinfo (CODESET) nowadays.  */
+  codeset = nl_langinfo (CODESET);
+
+#  ifdef __CYGWIN__
+  /* Cygwin < 1.7 does not have locales.  nl_langinfo (CODESET) always
+     returns "US-ASCII".  Return the suffix of the locale name from the
+     environment variables (if present) or the codepage as a number.  */
+  if (codeset != NULL && strcmp (codeset, "US-ASCII") == 0)
+    {
+      const char *locale;
+      static char buf[2 + 10 + 1];
+
+      locale = getenv ("LC_ALL");
+      if (locale == NULL || locale[0] == '\0')
+        {
+          locale = getenv ("LC_CTYPE");
+          if (locale == NULL || locale[0] == '\0')
+            locale = getenv ("LANG");
+        }
+      if (locale != NULL && locale[0] != '\0')
+        {
+          /* If the locale name contains an encoding after the dot, return
+             it.  */
+          const char *dot = strchr (locale, '.');
+
+          if (dot != NULL)
+            {
+              const char *modifier;
+
+              dot++;
+              /* Look for the possible @... trailer and remove it, if any.  */
+              modifier = strchr (dot, '@');
+              if (modifier == NULL)
+                return dot;
+              if (modifier - dot < sizeof (buf))
+                {
+                  memcpy (buf, dot, modifier - dot);
+                  buf [modifier - dot] = '\0';
+                  return buf;
+                }
+            }
+        }
+
+      /* The Windows API has a function returning the locale's codepage as a
+         number: GetACP().  This encoding is used by Cygwin, unless the user
+         has set the environment variable CYGWIN=codepage:oem (which very few
+         people do).
+         Output directed to console windows needs to be converted (to
+         GetOEMCP() if the console is using a raster font, or to
+         GetConsoleOutputCP() if it is using a TrueType font).  Cygwin does
+         this conversion transparently (see winsup/cygwin/fhandler_console.cc),
+         converting to GetConsoleOutputCP().  This leads to correct results,
+         except when SetConsoleOutputCP has been called and a raster font is
+         in use.  */
+      sprintf (buf, "CP%u", GetACP ());
+      codeset = buf;
+    }
+#  endif
+
+  if (codeset == NULL)
+    /* The canonical name cannot be determined.  */
+    codeset = "";
+
+# elif defined WINDOWS_NATIVE
+
+  static char buf[2 + 10 + 1];
+
+  /* The Windows API has a function returning the locale's codepage as
+     a number, but the value doesn't change according to what the
+     'setlocale' call specified.  So we use it as a last resort, in
+     case the string returned by 'setlocale' doesn't specify the
+     codepage.  */
+  char *current_locale = setlocale (LC_ALL, NULL);
+  char *pdot;
+
+  /* If they set different locales for different categories,
+     'setlocale' will return a semi-colon separated list of locale
+     values.  To make sure we use the correct one, we choose LC_CTYPE.  */
+  if (strchr (current_locale, ';'))
+    current_locale = setlocale (LC_CTYPE, NULL);
+
+  pdot = strrchr (current_locale, '.');
+  if (pdot && 2 + strlen (pdot + 1) + 1 <= sizeof (buf))
+    sprintf (buf, "CP%s", pdot + 1);
+  else
+    {
+      /* The Windows API has a function returning the locale's codepage as a
+        number: GetACP().
+        When the output goes to a console window, it needs to be provided in
+        GetOEMCP() encoding if the console is using a raster font, or in
+        GetConsoleOutputCP() encoding if it is using a TrueType font.
+        But in GUI programs and for output sent to files and pipes, GetACP()
+        encoding is the best bet.  */
+      sprintf (buf, "CP%u", GetACP ());
+    }
+  codeset = buf;
+
+# elif defined OS2
+
+  const char *locale;
+  static char buf[2 + 10 + 1];
+  ULONG cp[3];
+  ULONG cplen;
+
+  codeset = NULL;
+
+  /* Allow user to override the codeset, as set in the operating system,
+     with standard language environment variables.  */
+  locale = getenv ("LC_ALL");
+  if (locale == NULL || locale[0] == '\0')
+    {
+      locale = getenv ("LC_CTYPE");
+      if (locale == NULL || locale[0] == '\0')
+        locale = getenv ("LANG");
+    }
+  if (locale != NULL && locale[0] != '\0')
+    {
+      /* If the locale name contains an encoding after the dot, return it.  */
+      const char *dot = strchr (locale, '.');
+
+      if (dot != NULL)
+        {
+          const char *modifier;
+
+          dot++;
+          /* Look for the possible @... trailer and remove it, if any.  */
+          modifier = strchr (dot, '@');
+          if (modifier == NULL)
+            return dot;
+          if (modifier - dot < sizeof (buf))
+            {
+              memcpy (buf, dot, modifier - dot);
+              buf [modifier - dot] = '\0';
+              return buf;
+            }
+        }
+
+      /* For the POSIX locale, don't use the system's codepage.  */
+      if (strcmp (locale, "C") == 0 || strcmp (locale, "POSIX") == 0)
+        codeset = "";
+    }
+
+  if (codeset == NULL)
+    {
+      /* OS/2 has a function returning the locale's codepage as a number.  */
+      if (DosQueryCp (sizeof (cp), cp, &cplen))
+        codeset = "";
+      else
+        {
+          sprintf (buf, "CP%u", cp[0]);
+          codeset = buf;
+        }
+    }
+
+# else
+
+#  error "Add code for other platforms here."
+
+# endif
+
+  /* Resolve alias.  */
+  {
+# ifdef alias_table_defined
+    /* On some platforms, UTF-8 locales are the most frequently used ones.
+       Speed up the common case and slow down the less common cases by
+       testing for this case first.  */
+#  if defined __OpenBSD__ || (defined __APPLE__ && defined __MACH__) || defined __sun || defined __CYGWIN__
+    if (strcmp (codeset, "UTF-8") == 0)
+      goto done_table_lookup;
+    else
+#  endif
+      {
+        const struct table_entry * const table = alias_table;
+        size_t const table_size =
+          sizeof (alias_table) / sizeof (struct table_entry);
+        /* The table is sorted.  Perform a binary search.  */
+        size_t hi = table_size;
+        size_t lo = 0;
+        while (lo < hi)
+          {
+            /* Invariant:
+               for i < lo, strcmp (table[i].alias, codeset) < 0,
+               for i >= hi, strcmp (table[i].alias, codeset) > 0.  */
+            size_t mid = (hi + lo) >> 1; /* >= lo, < hi */
+            int cmp = strcmp (table[mid].alias, codeset);
+            if (cmp < 0)
+              lo = mid + 1;
+            else if (cmp > 0)
+              hi = mid;
+            else
+              {
+                /* Found an i with
+                     strcmp (table[i].alias, codeset) == 0.  */
+                codeset = table[mid].canonical;
+                goto done_table_lookup;
+              }
+          }
+      }
+    if (0)
+      done_table_lookup: ;
+    else
+# endif
+      {
+        /* Did not find it in the table.  */
+        /* On Mac OS X, all modern locales use the UTF-8 encoding.
+           BeOS and Haiku have a single locale, and it has UTF-8 encoding.  */
+# if (defined __APPLE__ && defined __MACH__) || defined __BEOS__ || defined __HAIKU__
+        codeset = "UTF-8";
+# else
+        /* Don't return an empty string.  GNU libc and GNU libiconv interpret
+           the empty string as denoting "the locale's character encoding",
+           thus GNU libiconv would call this function a second time.  */
+        if (codeset[0] == '\0')
+          codeset = "ASCII";
+# endif
+      }
+  }
+
+#else
+
+  /* On old systems which lack it, use setlocale or getenv.  */
+  const char *locale = NULL;
+
+  /* But most old systems don't have a complete set of locales.  Some
+     (like DJGPP) have only the C locale.  Therefore we don't use setlocale
+     here; it would return "C" when it doesn't support the locale name the
+     user has set.  */
+# if 0
+  locale = setlocale (LC_CTYPE, NULL);
+# endif
+  if (locale == NULL || locale[0] == '\0')
+    {
+      locale = getenv ("LC_ALL");
+      if (locale == NULL || locale[0] == '\0')
+        {
+          locale = getenv ("LC_CTYPE");
+          if (locale == NULL || locale[0] == '\0')
+            locale = getenv ("LANG");
+            if (locale == NULL)
+              locale = "";
+        }
+    }
+
+  /* Map locale name to canonical encoding name.  */
+  {
+# ifdef locale_table_defined
+    const struct table_entry * const table = locale_table;
+    size_t const table_size =
+      sizeof (locale_table) / sizeof (struct table_entry);
+    /* The table is sorted.  Perform a binary search.  */
+    size_t hi = table_size;
+    size_t lo = 0;
+    while (lo < hi)
+      {
+        /* Invariant:
+           for i < lo, strcmp (table[i].locale, locale) < 0,
+           for i >= hi, strcmp (table[i].locale, locale) > 0.  */
+        size_t mid = (hi + lo) >> 1; /* >= lo, < hi */
+        int cmp = strcmp (table[mid].locale, locale);
+        if (cmp < 0)
+          lo = mid + 1;
+        else if (cmp > 0)
+          hi = mid;
+        else
+          {
+            /* Found an i with
+                 strcmp (table[i].locale, locale) == 0.  */
+            codeset = table[mid].canonical;
+            goto done_table_lookup;
+          }
+      }
+    if (0)
+      done_table_lookup: ;
+    else
+# endif
+      {
+        /* Did not find it in the table.  */
+        /* On Mac OS X, all modern locales use the UTF-8 encoding.
+           BeOS and Haiku have a single locale, and it has UTF-8 encoding.  */
+# if (defined __APPLE__ && defined __MACH__) || defined __BEOS__ || defined __HAIKU__
+        codeset = "UTF-8";
+# else
+        /* The canonical name cannot be determined.  */
+        /* Don't return an empty string.  GNU libc and GNU libiconv interpret
+           the empty string as denoting "the locale's character encoding",
+           thus GNU libiconv would call this function a second time.  */
+        codeset = "ASCII";
+# endif
+      }
+  }
+
+#endif
+
+#ifdef DARWIN7
+  /* Mac OS X sets MB_CUR_MAX to 1 when LC_ALL=C, and "UTF-8"
+     (the default codeset) does not work when MB_CUR_MAX is 1.  */
+  if (strcmp (codeset, "UTF-8") == 0 && MB_CUR_MAX_L (uselocale (NULL)) <= 1)
+    codeset = "ASCII";
+#endif
+
+  return codeset;
+}
diff --git a/lib/localcharset.h b/lib/localcharset.h
new file mode 100644
index 0000000000..e4ba2960ba
--- /dev/null
+++ b/lib/localcharset.h
@@ -0,0 +1,134 @@
+/* Determine a canonical name for the current locale's character encoding.
+   Copyright (C) 2000-2003, 2009-2018 Free Software Foundation, Inc.
+   This file is part of the GNU CHARSET Library.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along
+   with this program; if not, see <https://www.gnu.org/licenses/>.  */
+
+#ifndef _LOCALCHARSET_H
+#define _LOCALCHARSET_H
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/* Determine the current locale's character encoding, and canonicalize it
+   into one of the canonical names listed below.
+   The result must not be freed; it is statically allocated.
+   If the canonical name cannot be determined, the result is a non-canonical
+   name.  */
+extern const char * locale_charset (void);
+
+/* About GNU canonical names for character encodings:
+
+   Every canonical name must be supported by GNU libiconv.  Support by GNU libc
+   is also desirable.
+
+   The name is case insensitive.  Usually an upper case MIME charset name is
+   preferred.
+
+   The current list of these GNU canonical names is:
+
+       name              MIME?             used by which systems
+                                    (darwin = Mac OS X, windows = native Windows)
+
+   ASCII, ANSI_X3.4-1968       glibc solaris freebsd netbsd darwin minix cygwin
+   ISO-8859-1              Y   glibc aix hpux irix osf solaris freebsd netbsd openbsd darwin cygwin
+   ISO-8859-2              Y   glibc aix hpux irix osf solaris freebsd netbsd openbsd darwin cygwin
+   ISO-8859-3              Y   glibc solaris cygwin
+   ISO-8859-4              Y   hpux osf solaris freebsd netbsd openbsd darwin
+   ISO-8859-5              Y   glibc aix hpux irix osf solaris freebsd netbsd openbsd darwin cygwin
+   ISO-8859-6              Y   glibc aix hpux solaris cygwin
+   ISO-8859-7              Y   glibc aix hpux irix osf solaris freebsd netbsd openbsd darwin cygwin
+   ISO-8859-8              Y   glibc aix hpux osf solaris cygwin
+   ISO-8859-9              Y   glibc aix hpux irix osf solaris freebsd darwin cygwin
+   ISO-8859-13                 glibc hpux solaris freebsd netbsd openbsd darwin cygwin
+   ISO-8859-14                 glibc cygwin
+   ISO-8859-15                 glibc aix irix osf solaris freebsd netbsd openbsd darwin cygwin
+   KOI8-R                  Y   glibc hpux solaris freebsd netbsd openbsd darwin
+   KOI8-U                  Y   glibc freebsd netbsd openbsd darwin cygwin
+   KOI8-T                      glibc
+   CP437                       dos
+   CP775                       dos
+   CP850                       aix osf dos
+   CP852                       dos
+   CP855                       dos
+   CP856                       aix
+   CP857                       dos
+   CP861                       dos
+   CP862                       dos
+   CP864                       dos
+   CP865                       dos
+   CP866                       freebsd netbsd openbsd darwin dos
+   CP869                       dos
+   CP874                       windows dos
+   CP922                       aix
+   CP932                       aix cygwin windows dos
+   CP943                       aix
+   CP949                       osf darwin windows dos
+   CP950                       windows dos
+   CP1046                      aix
+   CP1124                      aix
+   CP1125                      dos
+   CP1129                      aix
+   CP1131                      freebsd darwin
+   CP1250                      windows
+   CP1251                      glibc hpux solaris freebsd netbsd openbsd darwin cygwin windows
+   CP1252                      aix windows
+   CP1253                      windows
+   CP1254                      windows
+   CP1255                      glibc windows
+   CP1256                      windows
+   CP1257                      windows
+   GB2312                  Y   glibc aix hpux irix solaris freebsd netbsd darwin cygwin
+   EUC-JP                  Y   glibc aix hpux irix osf solaris freebsd netbsd darwin cygwin
+   EUC-KR                  Y   glibc aix hpux irix osf solaris freebsd netbsd darwin cygwin
+   EUC-TW                      glibc aix hpux irix osf solaris netbsd
+   BIG5                    Y   glibc aix hpux osf solaris freebsd netbsd darwin cygwin
+   BIG5-HKSCS                  glibc hpux solaris netbsd darwin
+   GBK                         glibc aix osf solaris freebsd darwin cygwin windows dos
+   GB18030                     glibc hpux solaris freebsd netbsd darwin
+   SHIFT_JIS               Y   hpux osf solaris freebsd netbsd darwin
+   JOHAB                       glibc solaris windows
+   TIS-620                     glibc aix hpux osf solaris cygwin
+   VISCII                  Y   glibc
+   TCVN5712-1                  glibc
+   ARMSCII-8                   glibc freebsd netbsd darwin
+   GEORGIAN-PS                 glibc cygwin
+   PT154                       glibc netbsd cygwin
+   HP-ROMAN8                   hpux
+   HP-ARABIC8                  hpux
+   HP-GREEK8                   hpux
+   HP-HEBREW8                  hpux
+   HP-TURKISH8                 hpux
+   HP-KANA8                    hpux
+   DEC-KANJI                   osf
+   DEC-HANYU                   osf
+   UTF-8                   Y   glibc aix hpux osf solaris netbsd darwin cygwin
+
+   Note: Names which are not marked as being a MIME name should not be used in
+   Internet protocols for information interchange (mail, news, etc.).
+
+   Note: ASCII and ANSI_X3.4-1968 are synonymous canonical names.  Applications
+   must understand both names and treat them as equivalent.
+ */
+
+
+#ifdef __cplusplus
+}
+#endif
+
+
+#endif /* _LOCALCHARSET_H */
diff --git a/lib/locale.in.h b/lib/locale.in.h
new file mode 100644
index 0000000000..804261dcad
--- /dev/null
+++ b/lib/locale.in.h
@@ -0,0 +1,219 @@
+/* A POSIX <locale.h>.
+   Copyright (C) 2007-2018 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#if __GNUC__ >= 3
+@PRAGMA_SYSTEM_HEADER@
+#endif
+@PRAGMA_COLUMNS@
+
+#if (defined _WIN32 && !defined __CYGWIN__ && defined __need_locale_t) \
+    || defined _GL_ALREADY_INCLUDING_LOCALE_H
+
+/* Special invocation convention:
+   - Inside mingw header files,
+   - To handle Solaris header files (through Solaris 10) when combined
+     with gettext's libintl.h.  */
+
+#@INCLUDE_NEXT@ @NEXT_LOCALE_H@
+
+#else
+/* Normal invocation convention.  */
+
+#ifndef _@GUARD_PREFIX@_LOCALE_H
+
+#define _GL_ALREADY_INCLUDING_LOCALE_H
+
+/* The include_next requires a split double-inclusion guard.  */
+#@INCLUDE_NEXT@ @NEXT_LOCALE_H@
+
+#undef _GL_ALREADY_INCLUDING_LOCALE_H
+
+#ifndef _@GUARD_PREFIX@_LOCALE_H
+#define _@GUARD_PREFIX@_LOCALE_H
+
+/* NetBSD 5.0 mis-defines NULL.  */
+#include <stddef.h>
+
+/* Mac OS X 10.5 defines the locale_t type in <xlocale.h>.  */
+#if @HAVE_XLOCALE_H@
+# include <xlocale.h>
+#endif
+
+/* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
+
+/* The definition of _GL_ARG_NONNULL is copied here.  */
+
+/* The definition of _GL_WARN_ON_USE is copied here.  */
+
+/* The LC_MESSAGES locale category is specified in POSIX, but not in ISO C.
+   On systems that don't define it, use the same value as GNU libintl.  */
+#if !defined LC_MESSAGES
+# define LC_MESSAGES 1729
+#endif
+
+/* Bionic libc's 'struct lconv' is just a dummy.  */
+#if @REPLACE_STRUCT_LCONV@
+# define lconv rpl_lconv
+struct lconv
+{
+  /* All 'char *' are actually 'const char *'.  */
+
+  /* Members that depend on the LC_NUMERIC category of the locale.  See
+     <http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap07.html#tag_07_03_04> */
+
+  /* Symbol used as decimal point.  */
+  char *decimal_point;
+  /* Symbol used to separate groups of digits to the left of the decimal
+     point.  */
+  char *thousands_sep;
+  /* Definition of the size of groups of digits to the left of the decimal
+     point.  */
+  char *grouping;
+
+  /* Members that depend on the LC_MONETARY category of the locale.  See
+     <http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap07.html#tag_07_03_03> */
+
+  /* Symbol used as decimal point.  */
+  char *mon_decimal_point;
+  /* Symbol used to separate groups of digits to the left of the decimal
+     point.  */
+  char *mon_thousands_sep;
+  /* Definition of the size of groups of digits to the left of the decimal
+     point.  */
+  char *mon_grouping;
+  /* Sign used to indicate a value >= 0.  */
+  char *positive_sign;
+  /* Sign used to indicate a value < 0.  */
+  char *negative_sign;
+
+  /* For formatting local currency.  */
+  /* Currency symbol (3 characters) followed by separator (1 character).  */
+  char *currency_symbol;
+  /* Number of digits after the decimal point.  */
+  char frac_digits;
+  /* For values >= 0: 1 if the currency symbol precedes the number, 0 if it
+     comes after the number.  */
+  char p_cs_precedes;
+  /* For values >= 0: Position of the sign.  */
+  char p_sign_posn;
+  /* For values >= 0: Placement of spaces between currency symbol, sign, and
+     number.  */
+  char p_sep_by_space;
+  /* For values < 0: 1 if the currency symbol precedes the number, 0 if it
+     comes after the number.  */
+  char n_cs_precedes;
+  /* For values < 0: Position of the sign.  */
+  char n_sign_posn;
+  /* For values < 0: Placement of spaces between currency symbol, sign, and
+     number.  */
+  char n_sep_by_space;
+
+  /* For formatting international currency.  */
+  /* Currency symbol (3 characters) followed by separator (1 character).  */
+  char *int_curr_symbol;
+  /* Number of digits after the decimal point.  */
+  char int_frac_digits;
+  /* For values >= 0: 1 if the currency symbol precedes the number, 0 if it
+     comes after the number.  */
+  char int_p_cs_precedes;
+  /* For values >= 0: Position of the sign.  */
+  char int_p_sign_posn;
+  /* For values >= 0: Placement of spaces between currency symbol, sign, and
+     number.  */
+  char int_p_sep_by_space;
+  /* For values < 0: 1 if the currency symbol precedes the number, 0 if it
+     comes after the number.  */
+  char int_n_cs_precedes;
+  /* For values < 0: Position of the sign.  */
+  char int_n_sign_posn;
+  /* For values < 0: Placement of spaces between currency symbol, sign, and
+     number.  */
+  char int_n_sep_by_space;
+};
+#endif
+
+#if @GNULIB_LOCALECONV@
+# if @REPLACE_LOCALECONV@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef localeconv
+#   define localeconv rpl_localeconv
+#  endif
+_GL_FUNCDECL_RPL (localeconv, struct lconv *, (void));
+_GL_CXXALIAS_RPL (localeconv, struct lconv *, (void));
+# else
+_GL_CXXALIAS_SYS (localeconv, struct lconv *, (void));
+# endif
+_GL_CXXALIASWARN (localeconv);
+#elif @REPLACE_STRUCT_LCONV@
+# undef localeconv
+# define localeconv localeconv_used_without_requesting_gnulib_module_localeconv
+#elif defined GNULIB_POSIXCHECK
+# undef localeconv
+# if HAVE_RAW_DECL_LOCALECONV
+_GL_WARN_ON_USE (localeconv,
+                 "localeconv returns too few information on some platforms - "
+                 "use gnulib module localeconv for portability");
+# endif
+#endif
+
+#if @GNULIB_SETLOCALE@
+# if @REPLACE_SETLOCALE@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef setlocale
+#   define setlocale rpl_setlocale
+#   define GNULIB_defined_setlocale 1
+#  endif
+_GL_FUNCDECL_RPL (setlocale, char *, (int category, const char *locale));
+_GL_CXXALIAS_RPL (setlocale, char *, (int category, const char *locale));
+# else
+_GL_CXXALIAS_SYS (setlocale, char *, (int category, const char *locale));
+# endif
+_GL_CXXALIASWARN (setlocale);
+#elif defined GNULIB_POSIXCHECK
+# undef setlocale
+# if HAVE_RAW_DECL_SETLOCALE
+_GL_WARN_ON_USE (setlocale, "setlocale works differently on native Windows - "
+                 "use gnulib module setlocale for portability");
+# endif
+#endif
+
+#if @GNULIB_DUPLOCALE@
+# if @REPLACE_DUPLOCALE@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef duplocale
+#   define duplocale rpl_duplocale
+#  endif
+_GL_FUNCDECL_RPL (duplocale, locale_t, (locale_t locale) _GL_ARG_NONNULL ((1)));
+_GL_CXXALIAS_RPL (duplocale, locale_t, (locale_t locale));
+# else
+#  if @HAVE_DUPLOCALE@
+_GL_CXXALIAS_SYS (duplocale, locale_t, (locale_t locale));
+#  endif
+# endif
+# if @HAVE_DUPLOCALE@
+_GL_CXXALIASWARN (duplocale);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef duplocale
+# if HAVE_RAW_DECL_DUPLOCALE
+_GL_WARN_ON_USE (duplocale, "duplocale is buggy on some glibc systems - "
+                 "use gnulib module duplocale for portability");
+# endif
+#endif
+
+#endif /* _@GUARD_PREFIX@_LOCALE_H */
+#endif /* _@GUARD_PREFIX@_LOCALE_H */
+#endif /* !(__need_locale_t || _GL_ALREADY_INCLUDING_LOCALE_H) */
diff --git a/lib/localeconv.c b/lib/localeconv.c
new file mode 100644
index 0000000000..87cfaceeae
--- /dev/null
+++ b/lib/localeconv.c
@@ -0,0 +1,103 @@
+/* Query locale dependent information for formatting numbers.
+   Copyright (C) 2012-2018 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <locale.h>
+
+#if HAVE_STRUCT_LCONV_DECIMAL_POINT
+
+/* Override for platforms where 'struct lconv' lacks the int_p_*, int_n_*
+   members.  */
+
+struct lconv *
+localeconv (void)
+{
+  static struct lconv result;
+# undef lconv
+# undef localeconv
+  struct lconv *sys_result = localeconv ();
+
+  result.decimal_point = sys_result->decimal_point;
+  result.thousands_sep = sys_result->thousands_sep;
+  result.grouping = sys_result->grouping;
+  result.mon_decimal_point = sys_result->mon_decimal_point;
+  result.mon_thousands_sep = sys_result->mon_thousands_sep;
+  result.mon_grouping = sys_result->mon_grouping;
+  result.positive_sign = sys_result->positive_sign;
+  result.negative_sign = sys_result->negative_sign;
+  result.currency_symbol = sys_result->currency_symbol;
+  result.frac_digits = sys_result->frac_digits;
+  result.p_cs_precedes = sys_result->p_cs_precedes;
+  result.p_sign_posn = sys_result->p_sign_posn;
+  result.p_sep_by_space = sys_result->p_sep_by_space;
+  result.n_cs_precedes = sys_result->n_cs_precedes;
+  result.n_sign_posn = sys_result->n_sign_posn;
+  result.n_sep_by_space = sys_result->n_sep_by_space;
+  result.int_curr_symbol = sys_result->int_curr_symbol;
+  result.int_frac_digits = sys_result->int_frac_digits;
+  result.int_p_cs_precedes = sys_result->p_cs_precedes;
+  result.int_p_sign_posn = sys_result->p_sign_posn;
+  result.int_p_sep_by_space = sys_result->p_sep_by_space;
+  result.int_n_cs_precedes = sys_result->n_cs_precedes;
+  result.int_n_sign_posn = sys_result->n_sign_posn;
+  result.int_n_sep_by_space = sys_result->n_sep_by_space;
+
+  return &result;
+}
+
+#else
+
+/* Override for platforms where 'struct lconv' is a dummy.  */
+
+# include <limits.h>
+
+struct lconv *
+localeconv (void)
+{
+  static /*const*/ struct lconv result =
+    {
+      /* decimal_point */ ".",
+      /* thousands_sep */ "",
+      /* grouping */ "",
+      /* mon_decimal_point */ "",
+      /* mon_thousands_sep */ "",
+      /* mon_grouping */ "",
+      /* positive_sign */ "",
+      /* negative_sign */ "",
+      /* currency_symbol */ "",
+      /* frac_digits */ CHAR_MAX,
+      /* p_cs_precedes */ CHAR_MAX,
+      /* p_sign_posn */ CHAR_MAX,
+      /* p_sep_by_space */ CHAR_MAX,
+      /* n_cs_precedes */ CHAR_MAX,
+      /* n_sign_posn */ CHAR_MAX,
+      /* n_sep_by_space */ CHAR_MAX,
+      /* int_curr_symbol */ "",
+      /* int_frac_digits */ CHAR_MAX,
+      /* int_p_cs_precedes */ CHAR_MAX,
+      /* int_p_sign_posn */ CHAR_MAX,
+      /* int_p_sep_by_space */ CHAR_MAX,
+      /* int_n_cs_precedes */ CHAR_MAX,
+      /* int_n_sign_posn */ CHAR_MAX,
+      /* int_n_sep_by_space */ CHAR_MAX
+    };
+
+  return &result;
+}
+
+#endif
diff --git a/lib/mbrtowc.c b/lib/mbrtowc.c
new file mode 100644
index 0000000000..2f6df287a5
--- /dev/null
+++ b/lib/mbrtowc.c
@@ -0,0 +1,458 @@
+/* Convert multibyte character to wide character.
+   Copyright (C) 1999-2002, 2005-2018 Free Software Foundation, Inc.
+   Written by Bruno Haible <[email-masked]>, 2008.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <wchar.h>
+
+#if C_LOCALE_MAYBE_EILSEQ
+# include "hard-locale.h"
+# include <locale.h>
+#endif
+
+#if GNULIB_defined_mbstate_t
+/* Implement mbrtowc() on top of mbtowc().  */
+
+# include <errno.h>
+# include <stdlib.h>
+
+# include "localcharset.h"
+# include "streq.h"
+# include "verify.h"
+
+# ifndef FALLTHROUGH
+#  if __GNUC__ < 7
+#   define FALLTHROUGH ((void) 0)
+#  else
+#   define FALLTHROUGH __attribute__ ((__fallthrough__))
+#  endif
+# endif
+
+/* Returns a classification of special values of the encoding of the current
+   locale.  */
+typedef enum {
+  enc_other,      /* other */
+  enc_utf8,       /* UTF-8 */
+  enc_eucjp,      /* EUC-JP */
+  enc_94,         /* EUC-KR, GB2312, BIG5 */
+  enc_euctw,      /* EUC-TW */
+  enc_gb18030,    /* GB18030 */
+  enc_sjis        /* SJIS */
+} enc_t;
+static inline enc_t
+locale_enc (void)
+{
+  const char *encoding = locale_charset ();
+  if (STREQ_OPT (encoding, "UTF-8", 'U', 'T', 'F', '-', '8', 0, 0, 0, 0))
+    return enc_utf8;
+  if (STREQ_OPT (encoding, "EUC-JP", 'E', 'U', 'C', '-', 'J', 'P', 0, 0, 0))
+    return enc_eucjp;
+  if (STREQ_OPT (encoding, "EUC-KR", 'E', 'U', 'C', '-', 'K', 'R', 0, 0, 0)
+      || STREQ_OPT (encoding, "GB2312", 'G', 'B', '2', '3', '1', '2', 0, 0, 0)
+      || STREQ_OPT (encoding, "BIG5", 'B', 'I', 'G', '5', 0, 0, 0, 0, 0))
+    return enc_94;
+  if (STREQ_OPT (encoding, "EUC-TW", 'E', 'U', 'C', '-', 'T', 'W', 0, 0, 0))
+    return enc_euctw;
+  if (STREQ_OPT (encoding, "GB18030", 'G', 'B', '1', '8', '0', '3', '0', 0, 0))
+    return enc_gb18030;
+  if (STREQ_OPT (encoding, "SJIS", 'S', 'J', 'I', 'S', 0, 0, 0, 0, 0))
+    return enc_sjis;
+  return enc_other;
+}
+
+#if GNULIB_WCHAR_SINGLE
+/* When we know that the locale does not change, provide a speedup by
+   caching the value of locale_enc.  */
+static int cached_locale_enc = -1;
+static inline enc_t
+locale_enc_cached (void)
+{
+  if (cached_locale_enc < 0)
+    cached_locale_enc = locale_enc ();
+  return cached_locale_enc;
+}
+#else
+/* By default, don't make assumptions, hence no caching.  */
+# define locale_enc_cached locale_enc
+#endif
+
+verify (sizeof (mbstate_t) >= 4);
+
+static char internal_state[4];
+
+size_t
+mbrtowc (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps)
+{
+  char *pstate = (char *)ps;
+
+  if (s == NULL)
+    {
+      pwc = NULL;
+      s = "";
+      n = 1;
+    }
+
+  if (n == 0)
+    return (size_t)(-2);
+
+  /* Here n > 0.  */
+
+  if (pstate == NULL)
+    pstate = internal_state;
+
+  {
+    size_t nstate = pstate[0];
+    char buf[4];
+    const char *p;
+    size_t m;
+
+    switch (nstate)
+      {
+      case 0:
+        p = s;
+        m = n;
+        break;
+      case 3:
+        buf[2] = pstate[3];
+        FALLTHROUGH;
+      case 2:
+        buf[1] = pstate[2];
+        FALLTHROUGH;
+      case 1:
+        buf[0] = pstate[1];
+        p = buf;
+        m = nstate;
+        buf[m++] = s[0];
+        if (n >= 2 && m < 4)
+          {
+            buf[m++] = s[1];
+            if (n >= 3 && m < 4)
+              buf[m++] = s[2];
+          }
+        break;
+      default:
+        errno = EINVAL;
+        return (size_t)(-1);
+      }
+
+    /* Here m > 0.  */
+
+# if __GLIBC__ || defined __UCLIBC__
+    /* Work around bug <https://sourceware.org/bugzilla/show_bug.cgi?id=9674> */
+    mbtowc (NULL, NULL, 0);
+# endif
+    {
+      int res = mbtowc (pwc, p, m);
+
+      if (res >= 0)
+        {
+          if (pwc != NULL && ((*pwc == 0) != (res == 0)))
+            abort ();
+          if (nstate >= (res > 0 ? res : 1))
+            abort ();
+          res -= nstate;
+          pstate[0] = 0;
+          return res;
+        }
+
+      /* mbtowc does not distinguish between invalid and incomplete multibyte
+         sequences.  But mbrtowc needs to make this distinction.
+         There are two possible approaches:
+           - Use iconv() and its return value.
+           - Use built-in knowledge about the possible encodings.
+         Given the low quality of implementation of iconv() on the systems that
+         lack mbrtowc(), we use the second approach.
+         The possible encodings are:
+           - 8-bit encodings,
+           - EUC-JP, EUC-KR, GB2312, EUC-TW, BIG5, GB18030, SJIS,
+           - UTF-8.
+         Use specialized code for each.  */
+      if (m >= 4 || m >= MB_CUR_MAX)
+        goto invalid;
+      /* Here MB_CUR_MAX > 1 and 0 < m < 4.  */
+      switch (locale_enc_cached ())
+        {
+        case enc_utf8: /* UTF-8 */
+          {
+            /* Cf. unistr/u8-mblen.c.  */
+            unsigned char c = (unsigned char) p[0];
+
+            if (c >= 0xc2)
+              {
+                if (c < 0xe0)
+                  {
+                    if (m == 1)
+                      goto incomplete;
+                  }
+                else if (c < 0xf0)
+                  {
+                    if (m == 1)
+                      goto incomplete;
+                    if (m == 2)
+                      {
+                        unsigned char c2 = (unsigned char) p[1];
+
+                        if ((c2 ^ 0x80) < 0x40
+                            && (c >= 0xe1 || c2 >= 0xa0)
+                            && (c != 0xed || c2 < 0xa0))
+                          goto incomplete;
+                      }
+                  }
+                else if (c <= 0xf4)
+                  {
+                    if (m == 1)
+                      goto incomplete;
+                    else /* m == 2 || m == 3 */
+                      {
+                        unsigned char c2 = (unsigned char) p[1];
+
+                        if ((c2 ^ 0x80) < 0x40
+                            && (c >= 0xf1 || c2 >= 0x90)
+                            && (c < 0xf4 || (c == 0xf4 && c2 < 0x90)))
+                          {
+                            if (m == 2)
+                              goto incomplete;
+                            else /* m == 3 */
+                              {
+                                unsigned char c3 = (unsigned char) p[2];
+
+                                if ((c3 ^ 0x80) < 0x40)
+                                  goto incomplete;
+                              }
+                          }
+                      }
+                  }
+              }
+            goto invalid;
+          }
+
+        /* As a reference for this code, you can use the GNU libiconv
+           implementation.  Look for uses of the RET_TOOFEW macro.  */
+
+        case enc_eucjp: /* EUC-JP */
+          {
+            if (m == 1)
+              {
+                unsigned char c = (unsigned char) p[0];
+
+                if ((c >= 0xa1 && c < 0xff) || c == 0x8e || c == 0x8f)
+                  goto incomplete;
+              }
+            if (m == 2)
+              {
+                unsigned char c = (unsigned char) p[0];
+
+                if (c == 0x8f)
+                  {
+                    unsigned char c2 = (unsigned char) p[1];
+
+                    if (c2 >= 0xa1 && c2 < 0xff)
+                      goto incomplete;
+                  }
+              }
+            goto invalid;
+          }
+
+        case enc_94: /* EUC-KR, GB2312, BIG5 */
+          {
+            if (m == 1)
+              {
+                unsigned char c = (unsigned char) p[0];
+
+                if (c >= 0xa1 && c < 0xff)
+                  goto incomplete;
+              }
+            goto invalid;
+          }
+
+        case enc_euctw: /* EUC-TW */
+          {
+            if (m == 1)
+              {
+                unsigned char c = (unsigned char) p[0];
+
+                if ((c >= 0xa1 && c < 0xff) || c == 0x8e)
+                  goto incomplete;
+              }
+            else /* m == 2 || m == 3 */
+              {
+                unsigned char c = (unsigned char) p[0];
+
+                if (c == 0x8e)
+                  goto incomplete;
+              }
+            goto invalid;
+          }
+
+        case enc_gb18030: /* GB18030 */
+          {
+            if (m == 1)
+              {
+                unsigned char c = (unsigned char) p[0];
+
+                if ((c >= 0x90 && c <= 0xe3) || (c >= 0xf8 && c <= 0xfe))
+                  goto incomplete;
+              }
+            else /* m == 2 || m == 3 */
+              {
+                unsigned char c = (unsigned char) p[0];
+
+                if (c >= 0x90 && c <= 0xe3)
+                  {
+                    unsigned char c2 = (unsigned char) p[1];
+
+                    if (c2 >= 0x30 && c2 <= 0x39)
+                      {
+                        if (m == 2)
+                          goto incomplete;
+                        else /* m == 3 */
+                          {
+                            unsigned char c3 = (unsigned char) p[2];
+
+                            if (c3 >= 0x81 && c3 <= 0xfe)
+                              goto incomplete;
+                          }
+                      }
+                  }
+              }
+            goto invalid;
+          }
+
+        case enc_sjis: /* SJIS */
+          {
+            if (m == 1)
+              {
+                unsigned char c = (unsigned char) p[0];
+
+                if ((c >= 0x81 && c <= 0x9f) || (c >= 0xe0 && c <= 0xea)
+                    || (c >= 0xf0 && c <= 0xf9))
+                  goto incomplete;
+              }
+            goto invalid;
+          }
+
+        default:
+          /* An unknown multibyte encoding.  */
+          goto incomplete;
+        }
+
+     incomplete:
+      {
+        size_t k = nstate;
+        /* Here 0 <= k < m < 4.  */
+        pstate[++k] = s[0];
+        if (k < m)
+          {
+            pstate[++k] = s[1];
+            if (k < m)
+              pstate[++k] = s[2];
+          }
+        if (k != m)
+          abort ();
+      }
+      pstate[0] = m;
+      return (size_t)(-2);
+
+     invalid:
+      errno = EILSEQ;
+      /* The conversion state is undefined, says POSIX.  */
+      return (size_t)(-1);
+    }
+  }
+}
+
+#else
+/* Override the system's mbrtowc() function.  */
+
+# undef mbrtowc
+
+size_t
+rpl_mbrtowc (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps)
+{
+  size_t ret;
+  wchar_t wc;
+
+# if MBRTOWC_NULL_ARG2_BUG || MBRTOWC_RETVAL_BUG || MBRTOWC_EMPTY_INPUT_BUG
+  if (s == NULL)
+    {
+      pwc = NULL;
+      s = "";
+      n = 1;
+    }
+# endif
+
+# if MBRTOWC_EMPTY_INPUT_BUG
+  if (n == 0)
+    return (size_t) -2;
+# endif
+
+  if (! pwc)
+    pwc = &wc;
+
+# if MBRTOWC_RETVAL_BUG
+  {
+    static mbstate_t internal_state;
+
+    /* Override mbrtowc's internal state.  We cannot call mbsinit() on the
+       hidden internal state, but we can call it on our variable.  */
+    if (ps == NULL)
+      ps = &internal_state;
+
+    if (!mbsinit (ps))
+      {
+        /* Parse the rest of the multibyte character byte for byte.  */
+        size_t count = 0;
+        for (; n > 0; s++, n--)
+          {
+            ret = mbrtowc (&wc, s, 1, ps);
+
+            if (ret == (size_t)(-1))
+              return (size_t)(-1);
+            count++;
+            if (ret != (size_t)(-2))
+              {
+                /* The multibyte character has been completed.  */
+                *pwc = wc;
+                return (wc == 0 ? 0 : count);
+              }
+          }
+        return (size_t)(-2);
+      }
+  }
+# endif
+
+  ret = mbrtowc (pwc, s, n, ps);
+
+# if MBRTOWC_NUL_RETVAL_BUG
+  if (ret < (size_t) -2 && !*pwc)
+    return 0;
+# endif
+
+# if C_LOCALE_MAYBE_EILSEQ
+  if ((size_t) -2 <= ret && n != 0 && ! hard_locale (LC_CTYPE))
+    {
+      unsigned char uc = *s;
+      *pwc = uc;
+      return 1;
+    }
+# endif
+
+  return ret;
+}
+
+#endif
diff --git a/lib/mbsinit.c b/lib/mbsinit.c
new file mode 100644
index 0000000000..e23a5ad318
--- /dev/null
+++ b/lib/mbsinit.c
@@ -0,0 +1,73 @@
+/* Test for initial conversion state.
+   Copyright (C) 2008-2018 Free Software Foundation, Inc.
+   Written by Bruno Haible <[email-masked]>, 2008.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <wchar.h>
+
+#include "verify.h"
+
+#if GNULIB_defined_mbstate_t
+
+/* Platforms that lack mbsinit() also lack mbrlen(), mbrtowc(), mbsrtowcs()
+   and wcrtomb(), wcsrtombs().
+   We assume that
+     - sizeof (mbstate_t) >= 4,
+     - only stateless encodings are supported (such as UTF-8 and EUC-JP, but
+       not ISO-2022 variants),
+     - for each encoding, the number of bytes for a wide character is <= 4.
+       (This maximum is attained for UTF-8, GB18030, EUC-TW.)
+   We define the meaning of mbstate_t as follows:
+     - In mb -> wc direction, mbstate_t's first byte contains the number of
+       buffered bytes (in the range 0..3), followed by up to 3 buffered bytes.
+       See mbrtowc.c.
+     - In wc -> mb direction, mbstate_t contains no information. In other
+       words, it is always in the initial state.  */
+
+verify (sizeof (mbstate_t) >= 4);
+
+int
+mbsinit (const mbstate_t *ps)
+{
+  const char *pstate = (const char *)ps;
+
+  return pstate == NULL || pstate[0] == 0;
+}
+
+#else
+
+int
+mbsinit (const mbstate_t *ps)
+{
+# if defined _WIN32 && !defined __CYGWIN__
+  /* Native Windows.  */
+#  ifdef __MINGW32__
+  /* On mingw, 'mbstate_t' is defined as 'int'.  */
+  return ps == NULL || *ps == 0;
+#  else
+  /* MSVC defines 'mbstate_t' as an 8-byte struct; the first 4-bytes matter.  */
+  return ps == NULL || *(const unsigned int *)ps == 0;
+#  endif
+# else
+  /* Minix, HP-UX 11.00, Solaris 2.6, Interix, ...  */
+  /* Maybe this definition works, maybe not...  */
+  return ps == NULL || *(const char *)ps == 0;
+# endif
+}
+
+#endif
diff --git a/lib/mbtowc-impl.h b/lib/mbtowc-impl.h
new file mode 100644
index 0000000000..633832f5fe
--- /dev/null
+++ b/lib/mbtowc-impl.h
@@ -0,0 +1,44 @@
+/* Convert multibyte character to wide character.
+   Copyright (C) 2011-2018 Free Software Foundation, Inc.
+   Written by Bruno Haible <[email-masked]>, 2011.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* We don't need a static internal state, because the encoding is not state
+   dependent, and when mbrtowc returns (size_t)(-2). we throw the result
+   away. */
+
+int
+mbtowc (wchar_t *pwc, const char *s, size_t n)
+{
+  if (s == NULL)
+    return 0;
+  else
+    {
+      mbstate_t state;
+      wchar_t wc;
+      size_t result;
+
+      memset (&state, 0, sizeof (mbstate_t));
+      result = mbrtowc (&wc, s, n, &state);
+      if (result == (size_t)-1 || result == (size_t)-2)
+        {
+          errno = EILSEQ;
+          return -1;
+        }
+      if (pwc != NULL)
+        *pwc = wc;
+      return (wc == 0 ? 0 : result);
+    }
+}
diff --git a/lib/mbtowc.c b/lib/mbtowc.c
new file mode 100644
index 0000000000..a212b221fe
--- /dev/null
+++ b/lib/mbtowc.c
@@ -0,0 +1,26 @@
+/* Convert multibyte character to wide character.
+   Copyright (C) 2011-2018 Free Software Foundation, Inc.
+   Written by Bruno Haible <[email-masked]>, 2011.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+#include <stdlib.h>
+
+#include <errno.h>
+#include <string.h>
+#include <wchar.h>
+
+#include "mbtowc-impl.h"
diff --git a/lib/nl_langinfo.c b/lib/nl_langinfo.c
new file mode 100644
index 0000000000..ea26730ecc
--- /dev/null
+++ b/lib/nl_langinfo.c
@@ -0,0 +1,366 @@
+/* nl_langinfo() replacement: query locale dependent information.
+
+   Copyright (C) 2007-2018 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <langinfo.h>
+
+#include <locale.h>
+#include <string.h>
+#if defined _WIN32 && ! defined __CYGWIN__
+# define WIN32_LEAN_AND_MEAN  /* avoid including junk */
+# include <windows.h>
+# include <stdio.h>
+#endif
+
+#if !REPLACE_NL_LANGINFO || GNULIB_defined_CODESET
+/* Return the codeset of the current locale, if this is easily deducible.
+   Otherwise, return "".  */
+static char *
+ctype_codeset (void)
+{
+  static char buf[2 + 10 + 1];
+  char const *locale = setlocale (LC_CTYPE, NULL);
+  char *codeset = buf;
+  size_t codesetlen;
+  codeset[0] = '\0';
+
+  if (locale && locale[0])
+    {
+      /* If the locale name contains an encoding after the dot, return it.  */
+      char *dot = strchr (locale, '.');
+
+      if (dot)
+        {
+          /* Look for the possible @... trailer and remove it, if any.  */
+          char *codeset_start = dot + 1;
+          char const *modifier = strchr (codeset_start, '@');
+
+          if (! modifier)
+            codeset = codeset_start;
+          else
+            {
+              codesetlen = modifier - codeset_start;
+              if (codesetlen < sizeof buf)
+                {
+                  codeset = memcpy (buf, codeset_start, codesetlen);
+                  codeset[codesetlen] = '\0';
+                }
+            }
+        }
+    }
+
+# if defined _WIN32 && ! defined __CYGWIN__
+  /* If setlocale is successful, it returns the number of the
+     codepage, as a string.  Otherwise, fall back on Windows API
+     GetACP, which returns the locale's codepage as a number (although
+     this doesn't change according to what the 'setlocale' call specified).
+     Either way, prepend "CP" to make it a valid codeset name.  */
+  codesetlen = strlen (codeset);
+  if (0 < codesetlen && codesetlen < sizeof buf - 2)
+    memmove (buf + 2, codeset, codesetlen + 1);
+  else
+    sprintf (buf + 2, "%u", GetACP ());
+  codeset = memcpy (buf, "CP", 2);
+# endif
+  return codeset;
+}
+#endif
+
+
+#if REPLACE_NL_LANGINFO
+
+/* Override nl_langinfo with support for added nl_item values.  */
+
+# undef nl_langinfo
+
+char *
+rpl_nl_langinfo (nl_item item)
+{
+  switch (item)
+    {
+# if GNULIB_defined_CODESET
+    case CODESET:
+      return ctype_codeset ();
+# endif
+# if GNULIB_defined_T_FMT_AMPM
+    case T_FMT_AMPM:
+      return (char *) "%I:%M:%S %p";
+# endif
+# if GNULIB_defined_ALTMON
+    case ALTMON_1:
+    case ALTMON_2:
+    case ALTMON_3:
+    case ALTMON_4:
+    case ALTMON_5:
+    case ALTMON_6:
+    case ALTMON_7:
+    case ALTMON_8:
+    case ALTMON_9:
+    case ALTMON_10:
+    case ALTMON_11:
+    case ALTMON_12:
+      /* We don't ship the appropriate localizations with gnulib.  Therefore,
+         treat ALTMON_i like MON_i.  */
+      item = item - ALTMON_1 + MON_1;
+      break;
+# endif
+# if GNULIB_defined_ERA
+    case ERA:
+      /* The format is not standardized.  In glibc it is a sequence of strings
+         of the form "direction:offset:start_date:end_date:era_name:era_format"
+         with an empty string at the end.  */
+      return (char *) "";
+    case ERA_D_FMT:
+      /* The %Ex conversion in strftime behaves like %x if the locale does not
+         have an alternative time format.  */
+      item = D_FMT;
+      break;
+    case ERA_D_T_FMT:
+      /* The %Ec conversion in strftime behaves like %c if the locale does not
+         have an alternative time format.  */
+      item = D_T_FMT;
+      break;
+    case ERA_T_FMT:
+      /* The %EX conversion in strftime behaves like %X if the locale does not
+         have an alternative time format.  */
+      item = T_FMT;
+      break;
+    case ALT_DIGITS:
+      /* The format is not standardized.  In glibc it is a sequence of 10
+         strings, appended in memory.  */
+      return (char *) "\0\0\0\0\0\0\0\0\0\0";
+# endif
+# if GNULIB_defined_YESEXPR || !FUNC_NL_LANGINFO_YESEXPR_WORKS
+    case YESEXPR:
+      return (char *) "^[yY]";
+    case NOEXPR:
+      return (char *) "^[nN]";
+# endif
+    default:
+      break;
+    }
+  return nl_langinfo (item);
+}
+
+#else
+
+/* Provide nl_langinfo from scratch, either for native MS-Windows, or
+   for old Unix platforms without locales, such as Linux libc5 or
+   BeOS.  */
+
+# include <time.h>
+
+char *
+nl_langinfo (nl_item item)
+{
+  static char nlbuf[100];
+  struct tm tmm = { 0 };
+
+  switch (item)
+    {
+    /* nl_langinfo items of the LC_CTYPE category */
+    case CODESET:
+      {
+        char *codeset = ctype_codeset ();
+        if (*codeset)
+          return codeset;
+      }
+# ifdef __BEOS__
+      return (char *) "UTF-8";
+# else
+      return (char *) "ISO-8859-1";
+# endif
+    /* nl_langinfo items of the LC_NUMERIC category */
+    case RADIXCHAR:
+      return localeconv () ->decimal_point;
+    case THOUSEP:
+      return localeconv () ->thousands_sep;
+# ifdef GROUPING
+    case GROUPING:
+      return localeconv () ->grouping;
+# endif
+    /* nl_langinfo items of the LC_TIME category.
+       TODO: Really use the locale.  */
+    case D_T_FMT:
+    case ERA_D_T_FMT:
+      return (char *) "%a %b %e %H:%M:%S %Y";
+    case D_FMT:
+    case ERA_D_FMT:
+      return (char *) "%m/%d/%y";
+    case T_FMT:
+    case ERA_T_FMT:
+      return (char *) "%H:%M:%S";
+    case T_FMT_AMPM:
+      return (char *) "%I:%M:%S %p";
+    case AM_STR:
+      if (!strftime (nlbuf, sizeof nlbuf, "%p", &tmm))
+        return (char *) "AM";
+      return nlbuf;
+    case PM_STR:
+      tmm.tm_hour = 12;
+      if (!strftime (nlbuf, sizeof nlbuf, "%p", &tmm))
+        return (char *) "PM";
+      return nlbuf;
+    case DAY_1:
+    case DAY_2:
+    case DAY_3:
+    case DAY_4:
+    case DAY_5:
+    case DAY_6:
+    case DAY_7:
+      {
+        static char const days[][sizeof "Wednesday"] = {
+          "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday",
+          "Friday", "Saturday"
+        };
+        tmm.tm_wday = item - DAY_1;
+        if (!strftime (nlbuf, sizeof nlbuf, "%A", &tmm))
+          return (char *) days[item - DAY_1];
+        return nlbuf;
+      }
+    case ABDAY_1:
+    case ABDAY_2:
+    case ABDAY_3:
+    case ABDAY_4:
+    case ABDAY_5:
+    case ABDAY_6:
+    case ABDAY_7:
+      {
+        static char const abdays[][sizeof "Sun"] = {
+          "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
+        };
+        tmm.tm_wday = item - ABDAY_1;
+        if (!strftime (nlbuf, sizeof nlbuf, "%a", &tmm))
+          return (char *) abdays[item - ABDAY_1];
+        return nlbuf;
+      }
+    {
+      static char const months[][sizeof "September"] = {
+        "January", "February", "March", "April", "May", "June", "July",
+        "September", "October", "November", "December"
+      };
+      case MON_1:
+      case MON_2:
+      case MON_3:
+      case MON_4:
+      case MON_5:
+      case MON_6:
+      case MON_7:
+      case MON_8:
+      case MON_9:
+      case MON_10:
+      case MON_11:
+      case MON_12:
+        tmm.tm_mon = item - MON_1;
+        if (!strftime (nlbuf, sizeof nlbuf, "%B", &tmm))
+          return (char *) months[item - MON_1];
+        return nlbuf;
+      case ALTMON_1:
+      case ALTMON_2:
+      case ALTMON_3:
+      case ALTMON_4:
+      case ALTMON_5:
+      case ALTMON_6:
+      case ALTMON_7:
+      case ALTMON_8:
+      case ALTMON_9:
+      case ALTMON_10:
+      case ALTMON_11:
+      case ALTMON_12:
+        tmm.tm_mon = item - ALTMON_1;
+        /* The platforms without nl_langinfo() don't support strftime with %OB.
+           We don't even need to try.  */
+        #if 0
+        if (!strftime (nlbuf, sizeof nlbuf, "%OB", &tmm))
+        #endif
+          if (!strftime (nlbuf, sizeof nlbuf, "%B", &tmm))
+            return (char *) months[item - ALTMON_1];
+        return nlbuf;
+    }
+    case ABMON_1:
+    case ABMON_2:
+    case ABMON_3:
+    case ABMON_4:
+    case ABMON_5:
+    case ABMON_6:
+    case ABMON_7:
+    case ABMON_8:
+    case ABMON_9:
+    case ABMON_10:
+    case ABMON_11:
+    case ABMON_12:
+      {
+        static char const abmonths[][sizeof "Jan"] = {
+          "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul",
+          "Sep", "Oct", "Nov", "Dec"
+        };
+        tmm.tm_mon = item - ABMON_1;
+        if (!strftime (nlbuf, sizeof nlbuf, "%b", &tmm))
+          return (char *) abmonths[item - ABMON_1];
+        return nlbuf;
+      }
+    case ERA:
+      return (char *) "";
+    case ALT_DIGITS:
+      return (char *) "\0\0\0\0\0\0\0\0\0\0";
+    /* nl_langinfo items of the LC_MONETARY category.  */
+    case CRNCYSTR:
+      return localeconv () ->currency_symbol;
+# ifdef INT_CURR_SYMBOL
+    case INT_CURR_SYMBOL:
+      return localeconv () ->int_curr_symbol;
+    case MON_DECIMAL_POINT:
+      return localeconv () ->mon_decimal_point;
+    case MON_THOUSANDS_SEP:
+      return localeconv () ->mon_thousands_sep;
+    case MON_GROUPING:
+      return localeconv () ->mon_grouping;
+    case POSITIVE_SIGN:
+      return localeconv () ->positive_sign;
+    case NEGATIVE_SIGN:
+      return localeconv () ->negative_sign;
+    case FRAC_DIGITS:
+      return & localeconv () ->frac_digits;
+    case INT_FRAC_DIGITS:
+      return & localeconv () ->int_frac_digits;
+    case P_CS_PRECEDES:
+      return & localeconv () ->p_cs_precedes;
+    case N_CS_PRECEDES:
+      return & localeconv () ->n_cs_precedes;
+    case P_SEP_BY_SPACE:
+      return & localeconv () ->p_sep_by_space;
+    case N_SEP_BY_SPACE:
+      return & localeconv () ->n_sep_by_space;
+    case P_SIGN_POSN:
+      return & localeconv () ->p_sign_posn;
+    case N_SIGN_POSN:
+      return & localeconv () ->n_sign_posn;
+# endif
+    /* nl_langinfo items of the LC_MESSAGES category
+       TODO: Really use the locale. */
+    case YESEXPR:
+      return (char *) "^[yY]";
+    case NOEXPR:
+      return (char *) "^[nN]";
+    default:
+      return (char *) "";
+    }
+}
+
+#endif
diff --git a/lib/regcomp.c b/lib/regcomp.c
new file mode 100644
index 0000000000..53eb226374
--- /dev/null
+++ b/lib/regcomp.c
@@ -0,0 +1,3944 @@
+/* Extended regular expression matching and search library.
+   Copyright (C) 2002-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Isamu Hasegawa <[email-masked]>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifdef _LIBC
+# include <locale/weight.h>
+#endif
+
+static reg_errcode_t re_compile_internal (regex_t *preg, const char * pattern,
+					  size_t length, reg_syntax_t syntax);
+static void re_compile_fastmap_iter (regex_t *bufp,
+				     const re_dfastate_t *init_state,
+				     char *fastmap);
+static reg_errcode_t init_dfa (re_dfa_t *dfa, size_t pat_len);
+#ifdef RE_ENABLE_I18N
+static void free_charset (re_charset_t *cset);
+#endif /* RE_ENABLE_I18N */
+static void free_workarea_compile (regex_t *preg);
+static reg_errcode_t create_initial_state (re_dfa_t *dfa);
+#ifdef RE_ENABLE_I18N
+static void optimize_utf8 (re_dfa_t *dfa);
+#endif
+static reg_errcode_t analyze (regex_t *preg);
+static reg_errcode_t preorder (bin_tree_t *root,
+			       reg_errcode_t (fn (void *, bin_tree_t *)),
+			       void *extra);
+static reg_errcode_t postorder (bin_tree_t *root,
+				reg_errcode_t (fn (void *, bin_tree_t *)),
+				void *extra);
+static reg_errcode_t optimize_subexps (void *extra, bin_tree_t *node);
+static reg_errcode_t lower_subexps (void *extra, bin_tree_t *node);
+static bin_tree_t *lower_subexp (reg_errcode_t *err, regex_t *preg,
+				 bin_tree_t *node);
+static reg_errcode_t calc_first (void *extra, bin_tree_t *node);
+static reg_errcode_t calc_next (void *extra, bin_tree_t *node);
+static reg_errcode_t link_nfa_nodes (void *extra, bin_tree_t *node);
+static Idx duplicate_node (re_dfa_t *dfa, Idx org_idx, unsigned int constraint);
+static Idx search_duplicated_node (const re_dfa_t *dfa, Idx org_node,
+				   unsigned int constraint);
+static reg_errcode_t calc_eclosure (re_dfa_t *dfa);
+static reg_errcode_t calc_eclosure_iter (re_node_set *new_set, re_dfa_t *dfa,
+					 Idx node, bool root);
+static reg_errcode_t calc_inveclosure (re_dfa_t *dfa);
+static Idx fetch_number (re_string_t *input, re_token_t *token,
+			 reg_syntax_t syntax);
+static int peek_token (re_token_t *token, re_string_t *input,
+			reg_syntax_t syntax);
+static bin_tree_t *parse (re_string_t *regexp, regex_t *preg,
+			  reg_syntax_t syntax, reg_errcode_t *err);
+static bin_tree_t *parse_reg_exp (re_string_t *regexp, regex_t *preg,
+				  re_token_t *token, reg_syntax_t syntax,
+				  Idx nest, reg_errcode_t *err);
+static bin_tree_t *parse_branch (re_string_t *regexp, regex_t *preg,
+				 re_token_t *token, reg_syntax_t syntax,
+				 Idx nest, reg_errcode_t *err);
+static bin_tree_t *parse_expression (re_string_t *regexp, regex_t *preg,
+				     re_token_t *token, reg_syntax_t syntax,
+				     Idx nest, reg_errcode_t *err);
+static bin_tree_t *parse_sub_exp (re_string_t *regexp, regex_t *preg,
+				  re_token_t *token, reg_syntax_t syntax,
+				  Idx nest, reg_errcode_t *err);
+static bin_tree_t *parse_dup_op (bin_tree_t *dup_elem, re_string_t *regexp,
+				 re_dfa_t *dfa, re_token_t *token,
+				 reg_syntax_t syntax, reg_errcode_t *err);
+static bin_tree_t *parse_bracket_exp (re_string_t *regexp, re_dfa_t *dfa,
+				      re_token_t *token, reg_syntax_t syntax,
+				      reg_errcode_t *err);
+static reg_errcode_t parse_bracket_element (bracket_elem_t *elem,
+					    re_string_t *regexp,
+					    re_token_t *token, int token_len,
+					    re_dfa_t *dfa,
+					    reg_syntax_t syntax,
+					    bool accept_hyphen);
+static reg_errcode_t parse_bracket_symbol (bracket_elem_t *elem,
+					  re_string_t *regexp,
+					  re_token_t *token);
+#ifdef RE_ENABLE_I18N
+static reg_errcode_t build_equiv_class (bitset_t sbcset,
+					re_charset_t *mbcset,
+					Idx *equiv_class_alloc,
+					const unsigned char *name);
+static reg_errcode_t build_charclass (RE_TRANSLATE_TYPE trans,
+				      bitset_t sbcset,
+				      re_charset_t *mbcset,
+				      Idx *char_class_alloc,
+				      const char *class_name,
+				      reg_syntax_t syntax);
+#else  /* not RE_ENABLE_I18N */
+static reg_errcode_t build_equiv_class (bitset_t sbcset,
+					const unsigned char *name);
+static reg_errcode_t build_charclass (RE_TRANSLATE_TYPE trans,
+				      bitset_t sbcset,
+				      const char *class_name,
+				      reg_syntax_t syntax);
+#endif /* not RE_ENABLE_I18N */
+static bin_tree_t *build_charclass_op (re_dfa_t *dfa,
+				       RE_TRANSLATE_TYPE trans,
+				       const char *class_name,
+				       const char *extra,
+				       bool non_match, reg_errcode_t *err);
+static bin_tree_t *create_tree (re_dfa_t *dfa,
+				bin_tree_t *left, bin_tree_t *right,
+				re_token_type_t type);
+static bin_tree_t *create_token_tree (re_dfa_t *dfa,
+				      bin_tree_t *left, bin_tree_t *right,
+				      const re_token_t *token);
+static bin_tree_t *duplicate_tree (const bin_tree_t *src, re_dfa_t *dfa);
+static void free_token (re_token_t *node);
+static reg_errcode_t free_tree (void *extra, bin_tree_t *node);
+static reg_errcode_t mark_opt_subexp (void *extra, bin_tree_t *node);
+
+/* This table gives an error message for each of the error codes listed
+   in regex.h.  Obviously the order here has to be same as there.
+   POSIX doesn't require that we do anything for REG_NOERROR,
+   but why not be nice?  */
+
+static const char __re_error_msgid[] =
+  {
+#define REG_NOERROR_IDX	0
+    gettext_noop ("Success")	/* REG_NOERROR */
+    "\0"
+#define REG_NOMATCH_IDX (REG_NOERROR_IDX + sizeof "Success")
+    gettext_noop ("No match")	/* REG_NOMATCH */
+    "\0"
+#define REG_BADPAT_IDX	(REG_NOMATCH_IDX + sizeof "No match")
+    gettext_noop ("Invalid regular expression") /* REG_BADPAT */
+    "\0"
+#define REG_ECOLLATE_IDX (REG_BADPAT_IDX + sizeof "Invalid regular expression")
+    gettext_noop ("Invalid collation character") /* REG_ECOLLATE */
+    "\0"
+#define REG_ECTYPE_IDX	(REG_ECOLLATE_IDX + sizeof "Invalid collation character")
+    gettext_noop ("Invalid character class name") /* REG_ECTYPE */
+    "\0"
+#define REG_EESCAPE_IDX	(REG_ECTYPE_IDX + sizeof "Invalid character class name")
+    gettext_noop ("Trailing backslash") /* REG_EESCAPE */
+    "\0"
+#define REG_ESUBREG_IDX	(REG_EESCAPE_IDX + sizeof "Trailing backslash")
+    gettext_noop ("Invalid back reference") /* REG_ESUBREG */
+    "\0"
+#define REG_EBRACK_IDX	(REG_ESUBREG_IDX + sizeof "Invalid back reference")
+    gettext_noop ("Unmatched [, [^, [:, [., or [=")	/* REG_EBRACK */
+    "\0"
+#define REG_EPAREN_IDX	(REG_EBRACK_IDX + sizeof "Unmatched [, [^, [:, [., or [=")
+    gettext_noop ("Unmatched ( or \\(") /* REG_EPAREN */
+    "\0"
+#define REG_EBRACE_IDX	(REG_EPAREN_IDX + sizeof "Unmatched ( or \\(")
+    gettext_noop ("Unmatched \\{") /* REG_EBRACE */
+    "\0"
+#define REG_BADBR_IDX	(REG_EBRACE_IDX + sizeof "Unmatched \\{")
+    gettext_noop ("Invalid content of \\{\\}") /* REG_BADBR */
+    "\0"
+#define REG_ERANGE_IDX	(REG_BADBR_IDX + sizeof "Invalid content of \\{\\}")
+    gettext_noop ("Invalid range end")	/* REG_ERANGE */
+    "\0"
+#define REG_ESPACE_IDX	(REG_ERANGE_IDX + sizeof "Invalid range end")
+    gettext_noop ("Memory exhausted") /* REG_ESPACE */
+    "\0"
+#define REG_BADRPT_IDX	(REG_ESPACE_IDX + sizeof "Memory exhausted")
+    gettext_noop ("Invalid preceding regular expression") /* REG_BADRPT */
+    "\0"
+#define REG_EEND_IDX	(REG_BADRPT_IDX + sizeof "Invalid preceding regular expression")
+    gettext_noop ("Premature end of regular expression") /* REG_EEND */
+    "\0"
+#define REG_ESIZE_IDX	(REG_EEND_IDX + sizeof "Premature end of regular expression")
+    gettext_noop ("Regular expression too big") /* REG_ESIZE */
+    "\0"
+#define REG_ERPAREN_IDX	(REG_ESIZE_IDX + sizeof "Regular expression too big")
+    gettext_noop ("Unmatched ) or \\)") /* REG_ERPAREN */
+  };
+
+static const size_t __re_error_msgid_idx[] =
+  {
+    REG_NOERROR_IDX,
+    REG_NOMATCH_IDX,
+    REG_BADPAT_IDX,
+    REG_ECOLLATE_IDX,
+    REG_ECTYPE_IDX,
+    REG_EESCAPE_IDX,
+    REG_ESUBREG_IDX,
+    REG_EBRACK_IDX,
+    REG_EPAREN_IDX,
+    REG_EBRACE_IDX,
+    REG_BADBR_IDX,
+    REG_ERANGE_IDX,
+    REG_ESPACE_IDX,
+    REG_BADRPT_IDX,
+    REG_EEND_IDX,
+    REG_ESIZE_IDX,
+    REG_ERPAREN_IDX
+  };
+
+/* Entry points for GNU code.  */
+
+/* re_compile_pattern is the GNU regular expression compiler: it
+   compiles PATTERN (of length LENGTH) and puts the result in BUFP.
+   Returns 0 if the pattern was valid, otherwise an error string.
+
+   Assumes the 'allocated' (and perhaps 'buffer') and 'translate' fields
+   are set in BUFP on entry.  */
+
+const char *
+re_compile_pattern (const char *pattern, size_t length,
+		    struct re_pattern_buffer *bufp)
+{
+  reg_errcode_t ret;
+
+  /* And GNU code determines whether or not to get register information
+     by passing null for the REGS argument to re_match, etc., not by
+     setting no_sub, unless RE_NO_SUB is set.  */
+  bufp->no_sub = !!(re_syntax_options & RE_NO_SUB);
+
+  /* Match anchors at newline.  */
+  bufp->newline_anchor = 1;
+
+  ret = re_compile_internal (bufp, pattern, length, re_syntax_options);
+
+  if (!ret)
+    return NULL;
+  return gettext (__re_error_msgid + __re_error_msgid_idx[(int) ret]);
+}
+#ifdef _LIBC
+weak_alias (__re_compile_pattern, re_compile_pattern)
+#endif
+
+/* Set by 're_set_syntax' to the current regexp syntax to recognize.  Can
+   also be assigned to arbitrarily: each pattern buffer stores its own
+   syntax, so it can be changed between regex compilations.  */
+/* This has no initializer because initialized variables in Emacs
+   become read-only after dumping.  */
+reg_syntax_t re_syntax_options;
+
+
+/* Specify the precise syntax of regexps for compilation.  This provides
+   for compatibility for various utilities which historically have
+   different, incompatible syntaxes.
+
+   The argument SYNTAX is a bit mask comprised of the various bits
+   defined in regex.h.  We return the old syntax.  */
+
+reg_syntax_t
+re_set_syntax (reg_syntax_t syntax)
+{
+  reg_syntax_t ret = re_syntax_options;
+
+  re_syntax_options = syntax;
+  return ret;
+}
+#ifdef _LIBC
+weak_alias (__re_set_syntax, re_set_syntax)
+#endif
+
+int
+re_compile_fastmap (struct re_pattern_buffer *bufp)
+{
+  re_dfa_t *dfa = bufp->buffer;
+  char *fastmap = bufp->fastmap;
+
+  memset (fastmap, '\0', sizeof (char) * SBC_MAX);
+  re_compile_fastmap_iter (bufp, dfa->init_state, fastmap);
+  if (dfa->init_state != dfa->init_state_word)
+    re_compile_fastmap_iter (bufp, dfa->init_state_word, fastmap);
+  if (dfa->init_state != dfa->init_state_nl)
+    re_compile_fastmap_iter (bufp, dfa->init_state_nl, fastmap);
+  if (dfa->init_state != dfa->init_state_begbuf)
+    re_compile_fastmap_iter (bufp, dfa->init_state_begbuf, fastmap);
+  bufp->fastmap_accurate = 1;
+  return 0;
+}
+#ifdef _LIBC
+weak_alias (__re_compile_fastmap, re_compile_fastmap)
+#endif
+
+static inline void
+__attribute__ ((always_inline))
+re_set_fastmap (char *fastmap, bool icase, int ch)
+{
+  fastmap[ch] = 1;
+  if (icase)
+    fastmap[tolower (ch)] = 1;
+}
+
+/* Helper function for re_compile_fastmap.
+   Compile fastmap for the initial_state INIT_STATE.  */
+
+static void
+re_compile_fastmap_iter (regex_t *bufp, const re_dfastate_t *init_state,
+			 char *fastmap)
+{
+  re_dfa_t *dfa = bufp->buffer;
+  Idx node_cnt;
+  bool icase = (dfa->mb_cur_max == 1 && (bufp->syntax & RE_ICASE));
+  for (node_cnt = 0; node_cnt < init_state->nodes.nelem; ++node_cnt)
+    {
+      Idx node = init_state->nodes.elems[node_cnt];
+      re_token_type_t type = dfa->nodes[node].type;
+
+      if (type == CHARACTER)
+	{
+	  re_set_fastmap (fastmap, icase, dfa->nodes[node].opr.c);
+#ifdef RE_ENABLE_I18N
+	  if ((bufp->syntax & RE_ICASE) && dfa->mb_cur_max > 1)
+	    {
+	      unsigned char buf[MB_LEN_MAX];
+	      unsigned char *p;
+	      wchar_t wc;
+	      mbstate_t state;
+
+	      p = buf;
+	      *p++ = dfa->nodes[node].opr.c;
+	      while (++node < dfa->nodes_len
+		     &&	dfa->nodes[node].type == CHARACTER
+		     && dfa->nodes[node].mb_partial)
+		*p++ = dfa->nodes[node].opr.c;
+	      memset (&state, '\0', sizeof (state));
+	      if (__mbrtowc (&wc, (const char *) buf, p - buf,
+			     &state) == p - buf
+		  && (__wcrtomb ((char *) buf, __towlower (wc), &state)
+		      != (size_t) -1))
+		re_set_fastmap (fastmap, false, buf[0]);
+	    }
+#endif
+	}
+      else if (type == SIMPLE_BRACKET)
+	{
+	  int i, ch;
+	  for (i = 0, ch = 0; i < BITSET_WORDS; ++i)
+	    {
+	      int j;
+	      bitset_word_t w = dfa->nodes[node].opr.sbcset[i];
+	      for (j = 0; j < BITSET_WORD_BITS; ++j, ++ch)
+		if (w & ((bitset_word_t) 1 << j))
+		  re_set_fastmap (fastmap, icase, ch);
+	    }
+	}
+#ifdef RE_ENABLE_I18N
+      else if (type == COMPLEX_BRACKET)
+	{
+	  re_charset_t *cset = dfa->nodes[node].opr.mbcset;
+	  Idx i;
+
+# ifdef _LIBC
+	  /* See if we have to try all bytes which start multiple collation
+	     elements.
+	     e.g. In da_DK, we want to catch 'a' since "aa" is a valid
+		  collation element, and don't catch 'b' since 'b' is
+		  the only collation element which starts from 'b' (and
+		  it is caught by SIMPLE_BRACKET).  */
+	      if (_NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES) != 0
+		  && (cset->ncoll_syms || cset->nranges))
+		{
+		  const int32_t *table = (const int32_t *)
+		    _NL_CURRENT (LC_COLLATE, _NL_COLLATE_TABLEMB);
+		  for (i = 0; i < SBC_MAX; ++i)
+		    if (table[i] < 0)
+		      re_set_fastmap (fastmap, icase, i);
+		}
+# endif /* _LIBC */
+
+	  /* See if we have to start the match at all multibyte characters,
+	     i.e. where we would not find an invalid sequence.  This only
+	     applies to multibyte character sets; for single byte character
+	     sets, the SIMPLE_BRACKET again suffices.  */
+	  if (dfa->mb_cur_max > 1
+	      && (cset->nchar_classes || cset->non_match || cset->nranges
+# ifdef _LIBC
+		  || cset->nequiv_classes
+# endif /* _LIBC */
+		 ))
+	    {
+	      unsigned char c = 0;
+	      do
+		{
+		  mbstate_t mbs;
+		  memset (&mbs, 0, sizeof (mbs));
+		  if (__mbrtowc (NULL, (char *) &c, 1, &mbs) == (size_t) -2)
+		    re_set_fastmap (fastmap, false, (int) c);
+		}
+	      while (++c != 0);
+	    }
+
+	  else
+	    {
+	      /* ... Else catch all bytes which can start the mbchars.  */
+	      for (i = 0; i < cset->nmbchars; ++i)
+		{
+		  char buf[256];
+		  mbstate_t state;
+		  memset (&state, '\0', sizeof (state));
+		  if (__wcrtomb (buf, cset->mbchars[i], &state) != (size_t) -1)
+		    re_set_fastmap (fastmap, icase, *(unsigned char *) buf);
+		  if ((bufp->syntax & RE_ICASE) && dfa->mb_cur_max > 1)
+		    {
+		      if (__wcrtomb (buf, __towlower (cset->mbchars[i]), &state)
+			  != (size_t) -1)
+			re_set_fastmap (fastmap, false, *(unsigned char *) buf);
+		    }
+		}
+	    }
+	}
+#endif /* RE_ENABLE_I18N */
+      else if (type == OP_PERIOD
+#ifdef RE_ENABLE_I18N
+	       || type == OP_UTF8_PERIOD
+#endif /* RE_ENABLE_I18N */
+	       || type == END_OF_RE)
+	{
+	  memset (fastmap, '\1', sizeof (char) * SBC_MAX);
+	  if (type == END_OF_RE)
+	    bufp->can_be_null = 1;
+	  return;
+	}
+    }
+}
+
+/* Entry point for POSIX code.  */
+/* regcomp takes a regular expression as a string and compiles it.
+
+   PREG is a regex_t *.  We do not expect any fields to be initialized,
+   since POSIX says we shouldn't.  Thus, we set
+
+     'buffer' to the compiled pattern;
+     'used' to the length of the compiled pattern;
+     'syntax' to RE_SYNTAX_POSIX_EXTENDED if the
+       REG_EXTENDED bit in CFLAGS is set; otherwise, to
+       RE_SYNTAX_POSIX_BASIC;
+     'newline_anchor' to REG_NEWLINE being set in CFLAGS;
+     'fastmap' to an allocated space for the fastmap;
+     'fastmap_accurate' to zero;
+     're_nsub' to the number of subexpressions in PATTERN.
+
+   PATTERN is the address of the pattern string.
+
+   CFLAGS is a series of bits which affect compilation.
+
+     If REG_EXTENDED is set, we use POSIX extended syntax; otherwise, we
+     use POSIX basic syntax.
+
+     If REG_NEWLINE is set, then . and [^...] don't match newline.
+     Also, regexec will try a match beginning after every newline.
+
+     If REG_ICASE is set, then we considers upper- and lowercase
+     versions of letters to be equivalent when matching.
+
+     If REG_NOSUB is set, then when PREG is passed to regexec, that
+     routine will report only success or failure, and nothing about the
+     registers.
+
+   It returns 0 if it succeeds, nonzero if it doesn't.  (See regex.h for
+   the return codes and their meanings.)  */
+
+int
+regcomp (regex_t *_Restrict_ preg, const char *_Restrict_ pattern, int cflags)
+{
+  reg_errcode_t ret;
+  reg_syntax_t syntax = ((cflags & REG_EXTENDED) ? RE_SYNTAX_POSIX_EXTENDED
+			 : RE_SYNTAX_POSIX_BASIC);
+
+  preg->buffer = NULL;
+  preg->allocated = 0;
+  preg->used = 0;
+
+  /* Try to allocate space for the fastmap.  */
+  preg->fastmap = re_malloc (char, SBC_MAX);
+  if (BE (preg->fastmap == NULL, 0))
+    return REG_ESPACE;
+
+  syntax |= (cflags & REG_ICASE) ? RE_ICASE : 0;
+
+  /* If REG_NEWLINE is set, newlines are treated differently.  */
+  if (cflags & REG_NEWLINE)
+    { /* REG_NEWLINE implies neither . nor [^...] match newline.  */
+      syntax &= ~RE_DOT_NEWLINE;
+      syntax |= RE_HAT_LISTS_NOT_NEWLINE;
+      /* It also changes the matching behavior.  */
+      preg->newline_anchor = 1;
+    }
+  else
+    preg->newline_anchor = 0;
+  preg->no_sub = !!(cflags & REG_NOSUB);
+  preg->translate = NULL;
+
+  ret = re_compile_internal (preg, pattern, strlen (pattern), syntax);
+
+  /* POSIX doesn't distinguish between an unmatched open-group and an
+     unmatched close-group: both are REG_EPAREN.  */
+  if (ret == REG_ERPAREN)
+    ret = REG_EPAREN;
+
+  /* We have already checked preg->fastmap != NULL.  */
+  if (BE (ret == REG_NOERROR, 1))
+    /* Compute the fastmap now, since regexec cannot modify the pattern
+       buffer.  This function never fails in this implementation.  */
+    (void) re_compile_fastmap (preg);
+  else
+    {
+      /* Some error occurred while compiling the expression.  */
+      re_free (preg->fastmap);
+      preg->fastmap = NULL;
+    }
+
+  return (int) ret;
+}
+#ifdef _LIBC
+libc_hidden_def (__regcomp)
+weak_alias (__regcomp, regcomp)
+#endif
+
+/* Returns a message corresponding to an error code, ERRCODE, returned
+   from either regcomp or regexec.   We don't use PREG here.  */
+
+size_t
+regerror (int errcode, const regex_t *_Restrict_ preg, char *_Restrict_ errbuf,
+	  size_t errbuf_size)
+{
+  const char *msg;
+  size_t msg_size;
+
+  if (BE (errcode < 0
+	  || errcode >= (int) (sizeof (__re_error_msgid_idx)
+			       / sizeof (__re_error_msgid_idx[0])), 0))
+    /* Only error codes returned by the rest of the code should be passed
+       to this routine.  If we are given anything else, or if other regex
+       code generates an invalid error code, then the program has a bug.
+       Dump core so we can fix it.  */
+    abort ();
+
+  msg = gettext (__re_error_msgid + __re_error_msgid_idx[errcode]);
+
+  msg_size = strlen (msg) + 1; /* Includes the null.  */
+
+  if (BE (errbuf_size != 0, 1))
+    {
+      size_t cpy_size = msg_size;
+      if (BE (msg_size > errbuf_size, 0))
+	{
+	  cpy_size = errbuf_size - 1;
+	  errbuf[cpy_size] = '\0';
+	}
+      memcpy (errbuf, msg, cpy_size);
+    }
+
+  return msg_size;
+}
+#ifdef _LIBC
+weak_alias (__regerror, regerror)
+#endif
+
+
+#ifdef RE_ENABLE_I18N
+/* This static array is used for the map to single-byte characters when
+   UTF-8 is used.  Otherwise we would allocate memory just to initialize
+   it the same all the time.  UTF-8 is the preferred encoding so this is
+   a worthwhile optimization.  */
+static const bitset_t utf8_sb_map =
+{
+  /* Set the first 128 bits.  */
+# if defined __GNUC__ && !defined __STRICT_ANSI__
+  [0 ... 0x80 / BITSET_WORD_BITS - 1] = BITSET_WORD_MAX
+# else
+#  if 4 * BITSET_WORD_BITS < ASCII_CHARS
+#   error "bitset_word_t is narrower than 32 bits"
+#  elif 3 * BITSET_WORD_BITS < ASCII_CHARS
+  BITSET_WORD_MAX, BITSET_WORD_MAX, BITSET_WORD_MAX,
+#  elif 2 * BITSET_WORD_BITS < ASCII_CHARS
+  BITSET_WORD_MAX, BITSET_WORD_MAX,
+#  elif 1 * BITSET_WORD_BITS < ASCII_CHARS
+  BITSET_WORD_MAX,
+#  endif
+  (BITSET_WORD_MAX
+   >> (SBC_MAX % BITSET_WORD_BITS == 0
+       ? 0
+       : BITSET_WORD_BITS - SBC_MAX % BITSET_WORD_BITS))
+# endif
+};
+#endif
+
+
+static void
+free_dfa_content (re_dfa_t *dfa)
+{
+  Idx i, j;
+
+  if (dfa->nodes)
+    for (i = 0; i < dfa->nodes_len; ++i)
+      free_token (dfa->nodes + i);
+  re_free (dfa->nexts);
+  for (i = 0; i < dfa->nodes_len; ++i)
+    {
+      if (dfa->eclosures != NULL)
+	re_node_set_free (dfa->eclosures + i);
+      if (dfa->inveclosures != NULL)
+	re_node_set_free (dfa->inveclosures + i);
+      if (dfa->edests != NULL)
+	re_node_set_free (dfa->edests + i);
+    }
+  re_free (dfa->edests);
+  re_free (dfa->eclosures);
+  re_free (dfa->inveclosures);
+  re_free (dfa->nodes);
+
+  if (dfa->state_table)
+    for (i = 0; i <= dfa->state_hash_mask; ++i)
+      {
+	struct re_state_table_entry *entry = dfa->state_table + i;
+	for (j = 0; j < entry->num; ++j)
+	  {
+	    re_dfastate_t *state = entry->array[j];
+	    free_state (state);
+	  }
+	re_free (entry->array);
+      }
+  re_free (dfa->state_table);
+#ifdef RE_ENABLE_I18N
+  if (dfa->sb_char != utf8_sb_map)
+    re_free (dfa->sb_char);
+#endif
+  re_free (dfa->subexp_map);
+#ifdef DEBUG
+  re_free (dfa->re_str);
+#endif
+
+  re_free (dfa);
+}
+
+
+/* Free dynamically allocated space used by PREG.  */
+
+void
+regfree (regex_t *preg)
+{
+  re_dfa_t *dfa = preg->buffer;
+  if (BE (dfa != NULL, 1))
+    {
+      lock_fini (dfa->lock);
+      free_dfa_content (dfa);
+    }
+  preg->buffer = NULL;
+  preg->allocated = 0;
+
+  re_free (preg->fastmap);
+  preg->fastmap = NULL;
+
+  re_free (preg->translate);
+  preg->translate = NULL;
+}
+#ifdef _LIBC
+libc_hidden_def (__regfree)
+weak_alias (__regfree, regfree)
+#endif
+
+/* Entry points compatible with 4.2 BSD regex library.  We don't define
+   them unless specifically requested.  */
+
+#if defined _REGEX_RE_COMP || defined _LIBC
+
+/* BSD has one and only one pattern buffer.  */
+static struct re_pattern_buffer re_comp_buf;
+
+char *
+# ifdef _LIBC
+/* Make these definitions weak in libc, so POSIX programs can redefine
+   these names if they don't use our functions, and still use
+   regcomp/regexec above without link errors.  */
+weak_function
+# endif
+re_comp (const char *s)
+{
+  reg_errcode_t ret;
+  char *fastmap;
+
+  if (!s)
+    {
+      if (!re_comp_buf.buffer)
+	return gettext ("No previous regular expression");
+      return 0;
+    }
+
+  if (re_comp_buf.buffer)
+    {
+      fastmap = re_comp_buf.fastmap;
+      re_comp_buf.fastmap = NULL;
+      __regfree (&re_comp_buf);
+      memset (&re_comp_buf, '\0', sizeof (re_comp_buf));
+      re_comp_buf.fastmap = fastmap;
+    }
+
+  if (re_comp_buf.fastmap == NULL)
+    {
+      re_comp_buf.fastmap = re_malloc (char, SBC_MAX);
+      if (re_comp_buf.fastmap == NULL)
+	return (char *) gettext (__re_error_msgid
+				 + __re_error_msgid_idx[(int) REG_ESPACE]);
+    }
+
+  /* Since 're_exec' always passes NULL for the 'regs' argument, we
+     don't need to initialize the pattern buffer fields which affect it.  */
+
+  /* Match anchors at newlines.  */
+  re_comp_buf.newline_anchor = 1;
+
+  ret = re_compile_internal (&re_comp_buf, s, strlen (s), re_syntax_options);
+
+  if (!ret)
+    return NULL;
+
+  /* Yes, we're discarding 'const' here if !HAVE_LIBINTL.  */
+  return (char *) gettext (__re_error_msgid + __re_error_msgid_idx[(int) ret]);
+}
+
+#ifdef _LIBC
+libc_freeres_fn (free_mem)
+{
+  __regfree (&re_comp_buf);
+}
+#endif
+
+#endif /* _REGEX_RE_COMP */
+
+/* Internal entry point.
+   Compile the regular expression PATTERN, whose length is LENGTH.
+   SYNTAX indicate regular expression's syntax.  */
+
+static reg_errcode_t
+re_compile_internal (regex_t *preg, const char * pattern, size_t length,
+		     reg_syntax_t syntax)
+{
+  reg_errcode_t err = REG_NOERROR;
+  re_dfa_t *dfa;
+  re_string_t regexp;
+
+  /* Initialize the pattern buffer.  */
+  preg->fastmap_accurate = 0;
+  preg->syntax = syntax;
+  preg->not_bol = preg->not_eol = 0;
+  preg->used = 0;
+  preg->re_nsub = 0;
+  preg->can_be_null = 0;
+  preg->regs_allocated = REGS_UNALLOCATED;
+
+  /* Initialize the dfa.  */
+  dfa = preg->buffer;
+  if (BE (preg->allocated < sizeof (re_dfa_t), 0))
+    {
+      /* If zero allocated, but buffer is non-null, try to realloc
+	 enough space.  This loses if buffer's address is bogus, but
+	 that is the user's responsibility.  If ->buffer is NULL this
+	 is a simple allocation.  */
+      dfa = re_realloc (preg->buffer, re_dfa_t, 1);
+      if (dfa == NULL)
+	return REG_ESPACE;
+      preg->allocated = sizeof (re_dfa_t);
+      preg->buffer = dfa;
+    }
+  preg->used = sizeof (re_dfa_t);
+
+  err = init_dfa (dfa, length);
+  if (BE (err == REG_NOERROR && lock_init (dfa->lock) != 0, 0))
+    err = REG_ESPACE;
+  if (BE (err != REG_NOERROR, 0))
+    {
+      free_dfa_content (dfa);
+      preg->buffer = NULL;
+      preg->allocated = 0;
+      return err;
+    }
+#ifdef DEBUG
+  /* Note: length+1 will not overflow since it is checked in init_dfa.  */
+  dfa->re_str = re_malloc (char, length + 1);
+  strncpy (dfa->re_str, pattern, length + 1);
+#endif
+
+  err = re_string_construct (&regexp, pattern, length, preg->translate,
+			     (syntax & RE_ICASE) != 0, dfa);
+  if (BE (err != REG_NOERROR, 0))
+    {
+    re_compile_internal_free_return:
+      free_workarea_compile (preg);
+      re_string_destruct (&regexp);
+      lock_fini (dfa->lock);
+      free_dfa_content (dfa);
+      preg->buffer = NULL;
+      preg->allocated = 0;
+      return err;
+    }
+
+  /* Parse the regular expression, and build a structure tree.  */
+  preg->re_nsub = 0;
+  dfa->str_tree = parse (&regexp, preg, syntax, &err);
+  if (BE (dfa->str_tree == NULL, 0))
+    goto re_compile_internal_free_return;
+
+  /* Analyze the tree and create the nfa.  */
+  err = analyze (preg);
+  if (BE (err != REG_NOERROR, 0))
+    goto re_compile_internal_free_return;
+
+#ifdef RE_ENABLE_I18N
+  /* If possible, do searching in single byte encoding to speed things up.  */
+  if (dfa->is_utf8 && !(syntax & RE_ICASE) && preg->translate == NULL)
+    optimize_utf8 (dfa);
+#endif
+
+  /* Then create the initial state of the dfa.  */
+  err = create_initial_state (dfa);
+
+  /* Release work areas.  */
+  free_workarea_compile (preg);
+  re_string_destruct (&regexp);
+
+  if (BE (err != REG_NOERROR, 0))
+    {
+      lock_fini (dfa->lock);
+      free_dfa_content (dfa);
+      preg->buffer = NULL;
+      preg->allocated = 0;
+    }
+
+  return err;
+}
+
+/* Initialize DFA.  We use the length of the regular expression PAT_LEN
+   as the initial length of some arrays.  */
+
+static reg_errcode_t
+init_dfa (re_dfa_t *dfa, size_t pat_len)
+{
+  __re_size_t table_size;
+#ifndef _LIBC
+  const char *codeset_name;
+#endif
+#ifdef RE_ENABLE_I18N
+  size_t max_i18n_object_size = MAX (sizeof (wchar_t), sizeof (wctype_t));
+#else
+  size_t max_i18n_object_size = 0;
+#endif
+  size_t max_object_size =
+    MAX (sizeof (struct re_state_table_entry),
+	 MAX (sizeof (re_token_t),
+	      MAX (sizeof (re_node_set),
+		   MAX (sizeof (regmatch_t),
+			max_i18n_object_size))));
+
+  memset (dfa, '\0', sizeof (re_dfa_t));
+
+  /* Force allocation of str_tree_storage the first time.  */
+  dfa->str_tree_storage_idx = BIN_TREE_STORAGE_SIZE;
+
+  /* Avoid overflows.  The extra "/ 2" is for the table_size doubling
+     calculation below, and for similar doubling calculations
+     elsewhere.  And it's <= rather than <, because some of the
+     doubling calculations add 1 afterwards.  */
+  if (BE (MIN (IDX_MAX, SIZE_MAX / max_object_size) / 2 <= pat_len, 0))
+    return REG_ESPACE;
+
+  dfa->nodes_alloc = pat_len + 1;
+  dfa->nodes = re_malloc (re_token_t, dfa->nodes_alloc);
+
+  /*  table_size = 2 ^ ceil(log pat_len) */
+  for (table_size = 1; ; table_size <<= 1)
+    if (table_size > pat_len)
+      break;
+
+  dfa->state_table = calloc (sizeof (struct re_state_table_entry), table_size);
+  dfa->state_hash_mask = table_size - 1;
+
+  dfa->mb_cur_max = MB_CUR_MAX;
+#ifdef _LIBC
+  if (dfa->mb_cur_max == 6
+      && strcmp (_NL_CURRENT (LC_CTYPE, _NL_CTYPE_CODESET_NAME), "UTF-8") == 0)
+    dfa->is_utf8 = 1;
+  dfa->map_notascii = (_NL_CURRENT_WORD (LC_CTYPE, _NL_CTYPE_MAP_TO_NONASCII)
+		       != 0);
+#else
+  codeset_name = nl_langinfo (CODESET);
+  if ((codeset_name[0] == 'U' || codeset_name[0] == 'u')
+      && (codeset_name[1] == 'T' || codeset_name[1] == 't')
+      && (codeset_name[2] == 'F' || codeset_name[2] == 'f')
+      && strcmp (codeset_name + 3 + (codeset_name[3] == '-'), "8") == 0)
+    dfa->is_utf8 = 1;
+
+  /* We check exhaustively in the loop below if this charset is a
+     superset of ASCII.  */
+  dfa->map_notascii = 0;
+#endif
+
+#ifdef RE_ENABLE_I18N
+  if (dfa->mb_cur_max > 1)
+    {
+      if (dfa->is_utf8)
+	dfa->sb_char = (re_bitset_ptr_t) utf8_sb_map;
+      else
+	{
+	  int i, j, ch;
+
+	  dfa->sb_char = (re_bitset_ptr_t) calloc (sizeof (bitset_t), 1);
+	  if (BE (dfa->sb_char == NULL, 0))
+	    return REG_ESPACE;
+
+	  /* Set the bits corresponding to single byte chars.  */
+	  for (i = 0, ch = 0; i < BITSET_WORDS; ++i)
+	    for (j = 0; j < BITSET_WORD_BITS; ++j, ++ch)
+	      {
+		wint_t wch = __btowc (ch);
+		if (wch != WEOF)
+		  dfa->sb_char[i] |= (bitset_word_t) 1 << j;
+# ifndef _LIBC
+		if (isascii (ch) && wch != ch)
+		  dfa->map_notascii = 1;
+# endif
+	      }
+	}
+    }
+#endif
+
+  if (BE (dfa->nodes == NULL || dfa->state_table == NULL, 0))
+    return REG_ESPACE;
+  return REG_NOERROR;
+}
+
+/* Initialize WORD_CHAR table, which indicate which character is
+   "word".  In this case "word" means that it is the word construction
+   character used by some operators like "\<", "\>", etc.  */
+
+static void
+init_word_char (re_dfa_t *dfa)
+{
+  int i = 0;
+  int j;
+  int ch = 0;
+  dfa->word_ops_used = 1;
+  if (BE (dfa->map_notascii == 0, 1))
+    {
+      /* Avoid uint32_t and uint64_t as some non-GCC platforms lack
+	 them, an issue when this code is used in Gnulib.  */
+      bitset_word_t bits0 = 0x00000000;
+      bitset_word_t bits1 = 0x03ff0000;
+      bitset_word_t bits2 = 0x87fffffe;
+      bitset_word_t bits3 = 0x07fffffe;
+      if (BITSET_WORD_BITS == 64)
+	{
+	  /* Pacify gcc -Woverflow on 32-bit platformns.  */
+	  dfa->word_char[0] = bits1 << 31 << 1 | bits0;
+	  dfa->word_char[1] = bits3 << 31 << 1 | bits2;
+	  i = 2;
+	}
+      else if (BITSET_WORD_BITS == 32)
+	{
+	  dfa->word_char[0] = bits0;
+	  dfa->word_char[1] = bits1;
+	  dfa->word_char[2] = bits2;
+	  dfa->word_char[3] = bits3;
+	  i = 4;
+	}
+      else
+        goto general_case;
+      ch = 128;
+
+      if (BE (dfa->is_utf8, 1))
+	{
+	  memset (&dfa->word_char[i], '\0', (SBC_MAX - ch) / 8);
+	  return;
+	}
+    }
+
+ general_case:
+  for (; i < BITSET_WORDS; ++i)
+    for (j = 0; j < BITSET_WORD_BITS; ++j, ++ch)
+      if (isalnum (ch) || ch == '_')
+	dfa->word_char[i] |= (bitset_word_t) 1 << j;
+}
+
+/* Free the work area which are only used while compiling.  */
+
+static void
+free_workarea_compile (regex_t *preg)
+{
+  re_dfa_t *dfa = preg->buffer;
+  bin_tree_storage_t *storage, *next;
+  for (storage = dfa->str_tree_storage; storage; storage = next)
+    {
+      next = storage->next;
+      re_free (storage);
+    }
+  dfa->str_tree_storage = NULL;
+  dfa->str_tree_storage_idx = BIN_TREE_STORAGE_SIZE;
+  dfa->str_tree = NULL;
+  re_free (dfa->org_indices);
+  dfa->org_indices = NULL;
+}
+
+/* Create initial states for all contexts.  */
+
+static reg_errcode_t
+create_initial_state (re_dfa_t *dfa)
+{
+  Idx first, i;
+  reg_errcode_t err;
+  re_node_set init_nodes;
+
+  /* Initial states have the epsilon closure of the node which is
+     the first node of the regular expression.  */
+  first = dfa->str_tree->first->node_idx;
+  dfa->init_node = first;
+  err = re_node_set_init_copy (&init_nodes, dfa->eclosures + first);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+
+  /* The back-references which are in initial states can epsilon transit,
+     since in this case all of the subexpressions can be null.
+     Then we add epsilon closures of the nodes which are the next nodes of
+     the back-references.  */
+  if (dfa->nbackref > 0)
+    for (i = 0; i < init_nodes.nelem; ++i)
+      {
+	Idx node_idx = init_nodes.elems[i];
+	re_token_type_t type = dfa->nodes[node_idx].type;
+
+	Idx clexp_idx;
+	if (type != OP_BACK_REF)
+	  continue;
+	for (clexp_idx = 0; clexp_idx < init_nodes.nelem; ++clexp_idx)
+	  {
+	    re_token_t *clexp_node;
+	    clexp_node = dfa->nodes + init_nodes.elems[clexp_idx];
+	    if (clexp_node->type == OP_CLOSE_SUBEXP
+		&& clexp_node->opr.idx == dfa->nodes[node_idx].opr.idx)
+	      break;
+	  }
+	if (clexp_idx == init_nodes.nelem)
+	  continue;
+
+	if (type == OP_BACK_REF)
+	  {
+	    Idx dest_idx = dfa->edests[node_idx].elems[0];
+	    if (!re_node_set_contains (&init_nodes, dest_idx))
+	      {
+		reg_errcode_t merge_err
+                  = re_node_set_merge (&init_nodes, dfa->eclosures + dest_idx);
+		if (merge_err != REG_NOERROR)
+		  return merge_err;
+		i = 0;
+	      }
+	  }
+      }
+
+  /* It must be the first time to invoke acquire_state.  */
+  dfa->init_state = re_acquire_state_context (&err, dfa, &init_nodes, 0);
+  /* We don't check ERR here, since the initial state must not be NULL.  */
+  if (BE (dfa->init_state == NULL, 0))
+    return err;
+  if (dfa->init_state->has_constraint)
+    {
+      dfa->init_state_word = re_acquire_state_context (&err, dfa, &init_nodes,
+						       CONTEXT_WORD);
+      dfa->init_state_nl = re_acquire_state_context (&err, dfa, &init_nodes,
+						     CONTEXT_NEWLINE);
+      dfa->init_state_begbuf = re_acquire_state_context (&err, dfa,
+							 &init_nodes,
+							 CONTEXT_NEWLINE
+							 | CONTEXT_BEGBUF);
+      if (BE (dfa->init_state_word == NULL || dfa->init_state_nl == NULL
+	      || dfa->init_state_begbuf == NULL, 0))
+	return err;
+    }
+  else
+    dfa->init_state_word = dfa->init_state_nl
+      = dfa->init_state_begbuf = dfa->init_state;
+
+  re_node_set_free (&init_nodes);
+  return REG_NOERROR;
+}
+
+#ifdef RE_ENABLE_I18N
+/* If it is possible to do searching in single byte encoding instead of UTF-8
+   to speed things up, set dfa->mb_cur_max to 1, clear is_utf8 and change
+   DFA nodes where needed.  */
+
+static void
+optimize_utf8 (re_dfa_t *dfa)
+{
+  Idx node;
+  int i;
+  bool mb_chars = false;
+  bool has_period = false;
+
+  for (node = 0; node < dfa->nodes_len; ++node)
+    switch (dfa->nodes[node].type)
+      {
+      case CHARACTER:
+	if (dfa->nodes[node].opr.c >= ASCII_CHARS)
+	  mb_chars = true;
+	break;
+      case ANCHOR:
+	switch (dfa->nodes[node].opr.ctx_type)
+	  {
+	  case LINE_FIRST:
+	  case LINE_LAST:
+	  case BUF_FIRST:
+	  case BUF_LAST:
+	    break;
+	  default:
+	    /* Word anchors etc. cannot be handled.  It's okay to test
+	       opr.ctx_type since constraints (for all DFA nodes) are
+	       created by ORing one or more opr.ctx_type values.  */
+	    return;
+	  }
+	break;
+      case OP_PERIOD:
+	has_period = true;
+	break;
+      case OP_BACK_REF:
+      case OP_ALT:
+      case END_OF_RE:
+      case OP_DUP_ASTERISK:
+      case OP_OPEN_SUBEXP:
+      case OP_CLOSE_SUBEXP:
+	break;
+      case COMPLEX_BRACKET:
+	return;
+      case SIMPLE_BRACKET:
+	/* Just double check.  */
+	{
+	  int rshift = (ASCII_CHARS % BITSET_WORD_BITS == 0
+			? 0
+			: BITSET_WORD_BITS - ASCII_CHARS % BITSET_WORD_BITS);
+	  for (i = ASCII_CHARS / BITSET_WORD_BITS; i < BITSET_WORDS; ++i)
+	    {
+	      if (dfa->nodes[node].opr.sbcset[i] >> rshift != 0)
+		return;
+	      rshift = 0;
+	    }
+	}
+	break;
+      default:
+	abort ();
+      }
+
+  if (mb_chars || has_period)
+    for (node = 0; node < dfa->nodes_len; ++node)
+      {
+	if (dfa->nodes[node].type == CHARACTER
+	    && dfa->nodes[node].opr.c >= ASCII_CHARS)
+	  dfa->nodes[node].mb_partial = 0;
+	else if (dfa->nodes[node].type == OP_PERIOD)
+	  dfa->nodes[node].type = OP_UTF8_PERIOD;
+      }
+
+  /* The search can be in single byte locale.  */
+  dfa->mb_cur_max = 1;
+  dfa->is_utf8 = 0;
+  dfa->has_mb_node = dfa->nbackref > 0 || has_period;
+}
+#endif
+
+/* Analyze the structure tree, and calculate "first", "next", "edest",
+   "eclosure", and "inveclosure".  */
+
+static reg_errcode_t
+analyze (regex_t *preg)
+{
+  re_dfa_t *dfa = preg->buffer;
+  reg_errcode_t ret;
+
+  /* Allocate arrays.  */
+  dfa->nexts = re_malloc (Idx, dfa->nodes_alloc);
+  dfa->org_indices = re_malloc (Idx, dfa->nodes_alloc);
+  dfa->edests = re_malloc (re_node_set, dfa->nodes_alloc);
+  dfa->eclosures = re_malloc (re_node_set, dfa->nodes_alloc);
+  if (BE (dfa->nexts == NULL || dfa->org_indices == NULL || dfa->edests == NULL
+	  || dfa->eclosures == NULL, 0))
+    return REG_ESPACE;
+
+  dfa->subexp_map = re_malloc (Idx, preg->re_nsub);
+  if (dfa->subexp_map != NULL)
+    {
+      Idx i;
+      for (i = 0; i < preg->re_nsub; i++)
+	dfa->subexp_map[i] = i;
+      preorder (dfa->str_tree, optimize_subexps, dfa);
+      for (i = 0; i < preg->re_nsub; i++)
+	if (dfa->subexp_map[i] != i)
+	  break;
+      if (i == preg->re_nsub)
+	{
+	  re_free (dfa->subexp_map);
+	  dfa->subexp_map = NULL;
+	}
+    }
+
+  ret = postorder (dfa->str_tree, lower_subexps, preg);
+  if (BE (ret != REG_NOERROR, 0))
+    return ret;
+  ret = postorder (dfa->str_tree, calc_first, dfa);
+  if (BE (ret != REG_NOERROR, 0))
+    return ret;
+  preorder (dfa->str_tree, calc_next, dfa);
+  ret = preorder (dfa->str_tree, link_nfa_nodes, dfa);
+  if (BE (ret != REG_NOERROR, 0))
+    return ret;
+  ret = calc_eclosure (dfa);
+  if (BE (ret != REG_NOERROR, 0))
+    return ret;
+
+  /* We only need this during the prune_impossible_nodes pass in regexec.c;
+     skip it if p_i_n will not run, as calc_inveclosure can be quadratic.  */
+  if ((!preg->no_sub && preg->re_nsub > 0 && dfa->has_plural_match)
+      || dfa->nbackref)
+    {
+      dfa->inveclosures = re_malloc (re_node_set, dfa->nodes_len);
+      if (BE (dfa->inveclosures == NULL, 0))
+	return REG_ESPACE;
+      ret = calc_inveclosure (dfa);
+    }
+
+  return ret;
+}
+
+/* Our parse trees are very unbalanced, so we cannot use a stack to
+   implement parse tree visits.  Instead, we use parent pointers and
+   some hairy code in these two functions.  */
+static reg_errcode_t
+postorder (bin_tree_t *root, reg_errcode_t (fn (void *, bin_tree_t *)),
+	   void *extra)
+{
+  bin_tree_t *node, *prev;
+
+  for (node = root; ; )
+    {
+      /* Descend down the tree, preferably to the left (or to the right
+	 if that's the only child).  */
+      while (node->left || node->right)
+	if (node->left)
+	  node = node->left;
+	else
+	  node = node->right;
+
+      do
+	{
+	  reg_errcode_t err = fn (extra, node);
+	  if (BE (err != REG_NOERROR, 0))
+	    return err;
+	  if (node->parent == NULL)
+	    return REG_NOERROR;
+	  prev = node;
+	  node = node->parent;
+	}
+      /* Go up while we have a node that is reached from the right.  */
+      while (node->right == prev || node->right == NULL);
+      node = node->right;
+    }
+}
+
+static reg_errcode_t
+preorder (bin_tree_t *root, reg_errcode_t (fn (void *, bin_tree_t *)),
+	  void *extra)
+{
+  bin_tree_t *node;
+
+  for (node = root; ; )
+    {
+      reg_errcode_t err = fn (extra, node);
+      if (BE (err != REG_NOERROR, 0))
+	return err;
+
+      /* Go to the left node, or up and to the right.  */
+      if (node->left)
+	node = node->left;
+      else
+	{
+	  bin_tree_t *prev = NULL;
+	  while (node->right == prev || node->right == NULL)
+	    {
+	      prev = node;
+	      node = node->parent;
+	      if (!node)
+		return REG_NOERROR;
+	    }
+	  node = node->right;
+	}
+    }
+}
+
+/* Optimization pass: if a SUBEXP is entirely contained, strip it and tell
+   re_search_internal to map the inner one's opr.idx to this one's.  Adjust
+   backreferences as well.  Requires a preorder visit.  */
+static reg_errcode_t
+optimize_subexps (void *extra, bin_tree_t *node)
+{
+  re_dfa_t *dfa = (re_dfa_t *) extra;
+
+  if (node->token.type == OP_BACK_REF && dfa->subexp_map)
+    {
+      int idx = node->token.opr.idx;
+      node->token.opr.idx = dfa->subexp_map[idx];
+      dfa->used_bkref_map |= 1 << node->token.opr.idx;
+    }
+
+  else if (node->token.type == SUBEXP
+	   && node->left && node->left->token.type == SUBEXP)
+    {
+      Idx other_idx = node->left->token.opr.idx;
+
+      node->left = node->left->left;
+      if (node->left)
+	node->left->parent = node;
+
+      dfa->subexp_map[other_idx] = dfa->subexp_map[node->token.opr.idx];
+      if (other_idx < BITSET_WORD_BITS)
+	dfa->used_bkref_map &= ~((bitset_word_t) 1 << other_idx);
+    }
+
+  return REG_NOERROR;
+}
+
+/* Lowering pass: Turn each SUBEXP node into the appropriate concatenation
+   of OP_OPEN_SUBEXP, the body of the SUBEXP (if any) and OP_CLOSE_SUBEXP.  */
+static reg_errcode_t
+lower_subexps (void *extra, bin_tree_t *node)
+{
+  regex_t *preg = (regex_t *) extra;
+  reg_errcode_t err = REG_NOERROR;
+
+  if (node->left && node->left->token.type == SUBEXP)
+    {
+      node->left = lower_subexp (&err, preg, node->left);
+      if (node->left)
+	node->left->parent = node;
+    }
+  if (node->right && node->right->token.type == SUBEXP)
+    {
+      node->right = lower_subexp (&err, preg, node->right);
+      if (node->right)
+	node->right->parent = node;
+    }
+
+  return err;
+}
+
+static bin_tree_t *
+lower_subexp (reg_errcode_t *err, regex_t *preg, bin_tree_t *node)
+{
+  re_dfa_t *dfa = preg->buffer;
+  bin_tree_t *body = node->left;
+  bin_tree_t *op, *cls, *tree1, *tree;
+
+  if (preg->no_sub
+      /* We do not optimize empty subexpressions, because otherwise we may
+	 have bad CONCAT nodes with NULL children.  This is obviously not
+	 very common, so we do not lose much.  An example that triggers
+	 this case is the sed "script" /\(\)/x.  */
+      && node->left != NULL
+      && (node->token.opr.idx >= BITSET_WORD_BITS
+	  || !(dfa->used_bkref_map
+	       & ((bitset_word_t) 1 << node->token.opr.idx))))
+    return node->left;
+
+  /* Convert the SUBEXP node to the concatenation of an
+     OP_OPEN_SUBEXP, the contents, and an OP_CLOSE_SUBEXP.  */
+  op = create_tree (dfa, NULL, NULL, OP_OPEN_SUBEXP);
+  cls = create_tree (dfa, NULL, NULL, OP_CLOSE_SUBEXP);
+  tree1 = body ? create_tree (dfa, body, cls, CONCAT) : cls;
+  tree = create_tree (dfa, op, tree1, CONCAT);
+  if (BE (tree == NULL || tree1 == NULL || op == NULL || cls == NULL, 0))
+    {
+      *err = REG_ESPACE;
+      return NULL;
+    }
+
+  op->token.opr.idx = cls->token.opr.idx = node->token.opr.idx;
+  op->token.opt_subexp = cls->token.opt_subexp = node->token.opt_subexp;
+  return tree;
+}
+
+/* Pass 1 in building the NFA: compute FIRST and create unlinked automaton
+   nodes.  Requires a postorder visit.  */
+static reg_errcode_t
+calc_first (void *extra, bin_tree_t *node)
+{
+  re_dfa_t *dfa = (re_dfa_t *) extra;
+  if (node->token.type == CONCAT)
+    {
+      node->first = node->left->first;
+      node->node_idx = node->left->node_idx;
+    }
+  else
+    {
+      node->first = node;
+      node->node_idx = re_dfa_add_node (dfa, node->token);
+      if (BE (node->node_idx == -1, 0))
+	return REG_ESPACE;
+      if (node->token.type == ANCHOR)
+	dfa->nodes[node->node_idx].constraint = node->token.opr.ctx_type;
+    }
+  return REG_NOERROR;
+}
+
+/* Pass 2: compute NEXT on the tree.  Preorder visit.  */
+static reg_errcode_t
+calc_next (void *extra, bin_tree_t *node)
+{
+  switch (node->token.type)
+    {
+    case OP_DUP_ASTERISK:
+      node->left->next = node;
+      break;
+    case CONCAT:
+      node->left->next = node->right->first;
+      node->right->next = node->next;
+      break;
+    default:
+      if (node->left)
+	node->left->next = node->next;
+      if (node->right)
+	node->right->next = node->next;
+      break;
+    }
+  return REG_NOERROR;
+}
+
+/* Pass 3: link all DFA nodes to their NEXT node (any order will do).  */
+static reg_errcode_t
+link_nfa_nodes (void *extra, bin_tree_t *node)
+{
+  re_dfa_t *dfa = (re_dfa_t *) extra;
+  Idx idx = node->node_idx;
+  reg_errcode_t err = REG_NOERROR;
+
+  switch (node->token.type)
+    {
+    case CONCAT:
+      break;
+
+    case END_OF_RE:
+      assert (node->next == NULL);
+      break;
+
+    case OP_DUP_ASTERISK:
+    case OP_ALT:
+      {
+	Idx left, right;
+	dfa->has_plural_match = 1;
+	if (node->left != NULL)
+	  left = node->left->first->node_idx;
+	else
+	  left = node->next->node_idx;
+	if (node->right != NULL)
+	  right = node->right->first->node_idx;
+	else
+	  right = node->next->node_idx;
+	assert (left > -1);
+	assert (right > -1);
+	err = re_node_set_init_2 (dfa->edests + idx, left, right);
+      }
+      break;
+
+    case ANCHOR:
+    case OP_OPEN_SUBEXP:
+    case OP_CLOSE_SUBEXP:
+      err = re_node_set_init_1 (dfa->edests + idx, node->next->node_idx);
+      break;
+
+    case OP_BACK_REF:
+      dfa->nexts[idx] = node->next->node_idx;
+      if (node->token.type == OP_BACK_REF)
+	err = re_node_set_init_1 (dfa->edests + idx, dfa->nexts[idx]);
+      break;
+
+    default:
+      assert (!IS_EPSILON_NODE (node->token.type));
+      dfa->nexts[idx] = node->next->node_idx;
+      break;
+    }
+
+  return err;
+}
+
+/* Duplicate the epsilon closure of the node ROOT_NODE.
+   Note that duplicated nodes have constraint INIT_CONSTRAINT in addition
+   to their own constraint.  */
+
+static reg_errcode_t
+duplicate_node_closure (re_dfa_t *dfa, Idx top_org_node, Idx top_clone_node,
+			Idx root_node, unsigned int init_constraint)
+{
+  Idx org_node, clone_node;
+  bool ok;
+  unsigned int constraint = init_constraint;
+  for (org_node = top_org_node, clone_node = top_clone_node;;)
+    {
+      Idx org_dest, clone_dest;
+      if (dfa->nodes[org_node].type == OP_BACK_REF)
+	{
+	  /* If the back reference epsilon-transit, its destination must
+	     also have the constraint.  Then duplicate the epsilon closure
+	     of the destination of the back reference, and store it in
+	     edests of the back reference.  */
+	  org_dest = dfa->nexts[org_node];
+	  re_node_set_empty (dfa->edests + clone_node);
+	  clone_dest = duplicate_node (dfa, org_dest, constraint);
+	  if (BE (clone_dest == -1, 0))
+	    return REG_ESPACE;
+	  dfa->nexts[clone_node] = dfa->nexts[org_node];
+	  ok = re_node_set_insert (dfa->edests + clone_node, clone_dest);
+	  if (BE (! ok, 0))
+	    return REG_ESPACE;
+	}
+      else if (dfa->edests[org_node].nelem == 0)
+	{
+	  /* In case of the node can't epsilon-transit, don't duplicate the
+	     destination and store the original destination as the
+	     destination of the node.  */
+	  dfa->nexts[clone_node] = dfa->nexts[org_node];
+	  break;
+	}
+      else if (dfa->edests[org_node].nelem == 1)
+	{
+	  /* In case of the node can epsilon-transit, and it has only one
+	     destination.  */
+	  org_dest = dfa->edests[org_node].elems[0];
+	  re_node_set_empty (dfa->edests + clone_node);
+	  /* If the node is root_node itself, it means the epsilon closure
+	     has a loop.  Then tie it to the destination of the root_node.  */
+	  if (org_node == root_node && clone_node != org_node)
+	    {
+	      ok = re_node_set_insert (dfa->edests + clone_node, org_dest);
+	      if (BE (! ok, 0))
+	        return REG_ESPACE;
+	      break;
+	    }
+	  /* In case the node has another constraint, append it.  */
+	  constraint |= dfa->nodes[org_node].constraint;
+	  clone_dest = duplicate_node (dfa, org_dest, constraint);
+	  if (BE (clone_dest == -1, 0))
+	    return REG_ESPACE;
+	  ok = re_node_set_insert (dfa->edests + clone_node, clone_dest);
+	  if (BE (! ok, 0))
+	    return REG_ESPACE;
+	}
+      else /* dfa->edests[org_node].nelem == 2 */
+	{
+	  /* In case of the node can epsilon-transit, and it has two
+	     destinations. In the bin_tree_t and DFA, that's '|' and '*'.   */
+	  org_dest = dfa->edests[org_node].elems[0];
+	  re_node_set_empty (dfa->edests + clone_node);
+	  /* Search for a duplicated node which satisfies the constraint.  */
+	  clone_dest = search_duplicated_node (dfa, org_dest, constraint);
+	  if (clone_dest == -1)
+	    {
+	      /* There is no such duplicated node, create a new one.  */
+	      reg_errcode_t err;
+	      clone_dest = duplicate_node (dfa, org_dest, constraint);
+	      if (BE (clone_dest == -1, 0))
+		return REG_ESPACE;
+	      ok = re_node_set_insert (dfa->edests + clone_node, clone_dest);
+	      if (BE (! ok, 0))
+		return REG_ESPACE;
+	      err = duplicate_node_closure (dfa, org_dest, clone_dest,
+					    root_node, constraint);
+	      if (BE (err != REG_NOERROR, 0))
+		return err;
+	    }
+	  else
+	    {
+	      /* There is a duplicated node which satisfies the constraint,
+		 use it to avoid infinite loop.  */
+	      ok = re_node_set_insert (dfa->edests + clone_node, clone_dest);
+	      if (BE (! ok, 0))
+		return REG_ESPACE;
+	    }
+
+	  org_dest = dfa->edests[org_node].elems[1];
+	  clone_dest = duplicate_node (dfa, org_dest, constraint);
+	  if (BE (clone_dest == -1, 0))
+	    return REG_ESPACE;
+	  ok = re_node_set_insert (dfa->edests + clone_node, clone_dest);
+	  if (BE (! ok, 0))
+	    return REG_ESPACE;
+	}
+      org_node = org_dest;
+      clone_node = clone_dest;
+    }
+  return REG_NOERROR;
+}
+
+/* Search for a node which is duplicated from the node ORG_NODE, and
+   satisfies the constraint CONSTRAINT.  */
+
+static Idx
+search_duplicated_node (const re_dfa_t *dfa, Idx org_node,
+			unsigned int constraint)
+{
+  Idx idx;
+  for (idx = dfa->nodes_len - 1; dfa->nodes[idx].duplicated && idx > 0; --idx)
+    {
+      if (org_node == dfa->org_indices[idx]
+	  && constraint == dfa->nodes[idx].constraint)
+	return idx; /* Found.  */
+    }
+  return -1; /* Not found.  */
+}
+
+/* Duplicate the node whose index is ORG_IDX and set the constraint CONSTRAINT.
+   Return the index of the new node, or -1 if insufficient storage is
+   available.  */
+
+static Idx
+duplicate_node (re_dfa_t *dfa, Idx org_idx, unsigned int constraint)
+{
+  Idx dup_idx = re_dfa_add_node (dfa, dfa->nodes[org_idx]);
+  if (BE (dup_idx != -1, 1))
+    {
+      dfa->nodes[dup_idx].constraint = constraint;
+      dfa->nodes[dup_idx].constraint |= dfa->nodes[org_idx].constraint;
+      dfa->nodes[dup_idx].duplicated = 1;
+
+      /* Store the index of the original node.  */
+      dfa->org_indices[dup_idx] = org_idx;
+    }
+  return dup_idx;
+}
+
+static reg_errcode_t
+calc_inveclosure (re_dfa_t *dfa)
+{
+  Idx src, idx;
+  bool ok;
+  for (idx = 0; idx < dfa->nodes_len; ++idx)
+    re_node_set_init_empty (dfa->inveclosures + idx);
+
+  for (src = 0; src < dfa->nodes_len; ++src)
+    {
+      Idx *elems = dfa->eclosures[src].elems;
+      for (idx = 0; idx < dfa->eclosures[src].nelem; ++idx)
+	{
+	  ok = re_node_set_insert_last (dfa->inveclosures + elems[idx], src);
+	  if (BE (! ok, 0))
+	    return REG_ESPACE;
+	}
+    }
+
+  return REG_NOERROR;
+}
+
+/* Calculate "eclosure" for all the node in DFA.  */
+
+static reg_errcode_t
+calc_eclosure (re_dfa_t *dfa)
+{
+  Idx node_idx;
+  bool incomplete;
+#ifdef DEBUG
+  assert (dfa->nodes_len > 0);
+#endif
+  incomplete = false;
+  /* For each nodes, calculate epsilon closure.  */
+  for (node_idx = 0; ; ++node_idx)
+    {
+      reg_errcode_t err;
+      re_node_set eclosure_elem;
+      if (node_idx == dfa->nodes_len)
+	{
+	  if (!incomplete)
+	    break;
+	  incomplete = false;
+	  node_idx = 0;
+	}
+
+#ifdef DEBUG
+      assert (dfa->eclosures[node_idx].nelem != -1);
+#endif
+
+      /* If we have already calculated, skip it.  */
+      if (dfa->eclosures[node_idx].nelem != 0)
+	continue;
+      /* Calculate epsilon closure of 'node_idx'.  */
+      err = calc_eclosure_iter (&eclosure_elem, dfa, node_idx, true);
+      if (BE (err != REG_NOERROR, 0))
+	return err;
+
+      if (dfa->eclosures[node_idx].nelem == 0)
+	{
+	  incomplete = true;
+	  re_node_set_free (&eclosure_elem);
+	}
+    }
+  return REG_NOERROR;
+}
+
+/* Calculate epsilon closure of NODE.  */
+
+static reg_errcode_t
+calc_eclosure_iter (re_node_set *new_set, re_dfa_t *dfa, Idx node, bool root)
+{
+  reg_errcode_t err;
+  Idx i;
+  re_node_set eclosure;
+  bool ok;
+  bool incomplete = false;
+  err = re_node_set_alloc (&eclosure, dfa->edests[node].nelem + 1);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+
+  /* This indicates that we are calculating this node now.
+     We reference this value to avoid infinite loop.  */
+  dfa->eclosures[node].nelem = -1;
+
+  /* If the current node has constraints, duplicate all nodes
+     since they must inherit the constraints.  */
+  if (dfa->nodes[node].constraint
+      && dfa->edests[node].nelem
+      && !dfa->nodes[dfa->edests[node].elems[0]].duplicated)
+    {
+      err = duplicate_node_closure (dfa, node, node, node,
+				    dfa->nodes[node].constraint);
+      if (BE (err != REG_NOERROR, 0))
+	return err;
+    }
+
+  /* Expand each epsilon destination nodes.  */
+  if (IS_EPSILON_NODE(dfa->nodes[node].type))
+    for (i = 0; i < dfa->edests[node].nelem; ++i)
+      {
+	re_node_set eclosure_elem;
+	Idx edest = dfa->edests[node].elems[i];
+	/* If calculating the epsilon closure of 'edest' is in progress,
+	   return intermediate result.  */
+	if (dfa->eclosures[edest].nelem == -1)
+	  {
+	    incomplete = true;
+	    continue;
+	  }
+	/* If we haven't calculated the epsilon closure of 'edest' yet,
+	   calculate now. Otherwise use calculated epsilon closure.  */
+	if (dfa->eclosures[edest].nelem == 0)
+	  {
+	    err = calc_eclosure_iter (&eclosure_elem, dfa, edest, false);
+	    if (BE (err != REG_NOERROR, 0))
+	      return err;
+	  }
+	else
+	  eclosure_elem = dfa->eclosures[edest];
+	/* Merge the epsilon closure of 'edest'.  */
+	err = re_node_set_merge (&eclosure, &eclosure_elem);
+	if (BE (err != REG_NOERROR, 0))
+	  return err;
+	/* If the epsilon closure of 'edest' is incomplete,
+	   the epsilon closure of this node is also incomplete.  */
+	if (dfa->eclosures[edest].nelem == 0)
+	  {
+	    incomplete = true;
+	    re_node_set_free (&eclosure_elem);
+	  }
+      }
+
+  /* An epsilon closure includes itself.  */
+  ok = re_node_set_insert (&eclosure, node);
+  if (BE (! ok, 0))
+    return REG_ESPACE;
+  if (incomplete && !root)
+    dfa->eclosures[node].nelem = 0;
+  else
+    dfa->eclosures[node] = eclosure;
+  *new_set = eclosure;
+  return REG_NOERROR;
+}
+
+/* Functions for token which are used in the parser.  */
+
+/* Fetch a token from INPUT.
+   We must not use this function inside bracket expressions.  */
+
+static void
+fetch_token (re_token_t *result, re_string_t *input, reg_syntax_t syntax)
+{
+  re_string_skip_bytes (input, peek_token (result, input, syntax));
+}
+
+/* Peek a token from INPUT, and return the length of the token.
+   We must not use this function inside bracket expressions.  */
+
+static int
+peek_token (re_token_t *token, re_string_t *input, reg_syntax_t syntax)
+{
+  unsigned char c;
+
+  if (re_string_eoi (input))
+    {
+      token->type = END_OF_RE;
+      return 0;
+    }
+
+  c = re_string_peek_byte (input, 0);
+  token->opr.c = c;
+
+  token->word_char = 0;
+#ifdef RE_ENABLE_I18N
+  token->mb_partial = 0;
+  if (input->mb_cur_max > 1 &&
+      !re_string_first_byte (input, re_string_cur_idx (input)))
+    {
+      token->type = CHARACTER;
+      token->mb_partial = 1;
+      return 1;
+    }
+#endif
+  if (c == '\\')
+    {
+      unsigned char c2;
+      if (re_string_cur_idx (input) + 1 >= re_string_length (input))
+	{
+	  token->type = BACK_SLASH;
+	  return 1;
+	}
+
+      c2 = re_string_peek_byte_case (input, 1);
+      token->opr.c = c2;
+      token->type = CHARACTER;
+#ifdef RE_ENABLE_I18N
+      if (input->mb_cur_max > 1)
+	{
+	  wint_t wc = re_string_wchar_at (input,
+					  re_string_cur_idx (input) + 1);
+	  token->word_char = IS_WIDE_WORD_CHAR (wc) != 0;
+	}
+      else
+#endif
+	token->word_char = IS_WORD_CHAR (c2) != 0;
+
+      switch (c2)
+	{
+	case '|':
+	  if (!(syntax & RE_LIMITED_OPS) && !(syntax & RE_NO_BK_VBAR))
+	    token->type = OP_ALT;
+	  break;
+	case '1': case '2': case '3': case '4': case '5':
+	case '6': case '7': case '8': case '9':
+	  if (!(syntax & RE_NO_BK_REFS))
+	    {
+	      token->type = OP_BACK_REF;
+	      token->opr.idx = c2 - '1';
+	    }
+	  break;
+	case '<':
+	  if (!(syntax & RE_NO_GNU_OPS))
+	    {
+	      token->type = ANCHOR;
+	      token->opr.ctx_type = WORD_FIRST;
+	    }
+	  break;
+	case '>':
+	  if (!(syntax & RE_NO_GNU_OPS))
+	    {
+	      token->type = ANCHOR;
+	      token->opr.ctx_type = WORD_LAST;
+	    }
+	  break;
+	case 'b':
+	  if (!(syntax & RE_NO_GNU_OPS))
+	    {
+	      token->type = ANCHOR;
+	      token->opr.ctx_type = WORD_DELIM;
+	    }
+	  break;
+	case 'B':
+	  if (!(syntax & RE_NO_GNU_OPS))
+	    {
+	      token->type = ANCHOR;
+	      token->opr.ctx_type = NOT_WORD_DELIM;
+	    }
+	  break;
+	case 'w':
+	  if (!(syntax & RE_NO_GNU_OPS))
+	    token->type = OP_WORD;
+	  break;
+	case 'W':
+	  if (!(syntax & RE_NO_GNU_OPS))
+	    token->type = OP_NOTWORD;
+	  break;
+	case 's':
+	  if (!(syntax & RE_NO_GNU_OPS))
+	    token->type = OP_SPACE;
+	  break;
+	case 'S':
+	  if (!(syntax & RE_NO_GNU_OPS))
+	    token->type = OP_NOTSPACE;
+	  break;
+	case '`':
+	  if (!(syntax & RE_NO_GNU_OPS))
+	    {
+	      token->type = ANCHOR;
+	      token->opr.ctx_type = BUF_FIRST;
+	    }
+	  break;
+	case '\'':
+	  if (!(syntax & RE_NO_GNU_OPS))
+	    {
+	      token->type = ANCHOR;
+	      token->opr.ctx_type = BUF_LAST;
+	    }
+	  break;
+	case '(':
+	  if (!(syntax & RE_NO_BK_PARENS))
+	    token->type = OP_OPEN_SUBEXP;
+	  break;
+	case ')':
+	  if (!(syntax & RE_NO_BK_PARENS))
+	    token->type = OP_CLOSE_SUBEXP;
+	  break;
+	case '+':
+	  if (!(syntax & RE_LIMITED_OPS) && (syntax & RE_BK_PLUS_QM))
+	    token->type = OP_DUP_PLUS;
+	  break;
+	case '?':
+	  if (!(syntax & RE_LIMITED_OPS) && (syntax & RE_BK_PLUS_QM))
+	    token->type = OP_DUP_QUESTION;
+	  break;
+	case '{':
+	  if ((syntax & RE_INTERVALS) && (!(syntax & RE_NO_BK_BRACES)))
+	    token->type = OP_OPEN_DUP_NUM;
+	  break;
+	case '}':
+	  if ((syntax & RE_INTERVALS) && (!(syntax & RE_NO_BK_BRACES)))
+	    token->type = OP_CLOSE_DUP_NUM;
+	  break;
+	default:
+	  break;
+	}
+      return 2;
+    }
+
+  token->type = CHARACTER;
+#ifdef RE_ENABLE_I18N
+  if (input->mb_cur_max > 1)
+    {
+      wint_t wc = re_string_wchar_at (input, re_string_cur_idx (input));
+      token->word_char = IS_WIDE_WORD_CHAR (wc) != 0;
+    }
+  else
+#endif
+    token->word_char = IS_WORD_CHAR (token->opr.c);
+
+  switch (c)
+    {
+    case '\n':
+      if (syntax & RE_NEWLINE_ALT)
+	token->type = OP_ALT;
+      break;
+    case '|':
+      if (!(syntax & RE_LIMITED_OPS) && (syntax & RE_NO_BK_VBAR))
+	token->type = OP_ALT;
+      break;
+    case '*':
+      token->type = OP_DUP_ASTERISK;
+      break;
+    case '+':
+      if (!(syntax & RE_LIMITED_OPS) && !(syntax & RE_BK_PLUS_QM))
+	token->type = OP_DUP_PLUS;
+      break;
+    case '?':
+      if (!(syntax & RE_LIMITED_OPS) && !(syntax & RE_BK_PLUS_QM))
+	token->type = OP_DUP_QUESTION;
+      break;
+    case '{':
+      if ((syntax & RE_INTERVALS) && (syntax & RE_NO_BK_BRACES))
+	token->type = OP_OPEN_DUP_NUM;
+      break;
+    case '}':
+      if ((syntax & RE_INTERVALS) && (syntax & RE_NO_BK_BRACES))
+	token->type = OP_CLOSE_DUP_NUM;
+      break;
+    case '(':
+      if (syntax & RE_NO_BK_PARENS)
+	token->type = OP_OPEN_SUBEXP;
+      break;
+    case ')':
+      if (syntax & RE_NO_BK_PARENS)
+	token->type = OP_CLOSE_SUBEXP;
+      break;
+    case '[':
+      token->type = OP_OPEN_BRACKET;
+      break;
+    case '.':
+      token->type = OP_PERIOD;
+      break;
+    case '^':
+      if (!(syntax & (RE_CONTEXT_INDEP_ANCHORS | RE_CARET_ANCHORS_HERE)) &&
+	  re_string_cur_idx (input) != 0)
+	{
+	  char prev = re_string_peek_byte (input, -1);
+	  if (!(syntax & RE_NEWLINE_ALT) || prev != '\n')
+	    break;
+	}
+      token->type = ANCHOR;
+      token->opr.ctx_type = LINE_FIRST;
+      break;
+    case '$':
+      if (!(syntax & RE_CONTEXT_INDEP_ANCHORS) &&
+	  re_string_cur_idx (input) + 1 != re_string_length (input))
+	{
+	  re_token_t next;
+	  re_string_skip_bytes (input, 1);
+	  peek_token (&next, input, syntax);
+	  re_string_skip_bytes (input, -1);
+	  if (next.type != OP_ALT && next.type != OP_CLOSE_SUBEXP)
+	    break;
+	}
+      token->type = ANCHOR;
+      token->opr.ctx_type = LINE_LAST;
+      break;
+    default:
+      break;
+    }
+  return 1;
+}
+
+/* Peek a token from INPUT, and return the length of the token.
+   We must not use this function out of bracket expressions.  */
+
+static int
+peek_token_bracket (re_token_t *token, re_string_t *input, reg_syntax_t syntax)
+{
+  unsigned char c;
+  if (re_string_eoi (input))
+    {
+      token->type = END_OF_RE;
+      return 0;
+    }
+  c = re_string_peek_byte (input, 0);
+  token->opr.c = c;
+
+#ifdef RE_ENABLE_I18N
+  if (input->mb_cur_max > 1 &&
+      !re_string_first_byte (input, re_string_cur_idx (input)))
+    {
+      token->type = CHARACTER;
+      return 1;
+    }
+#endif /* RE_ENABLE_I18N */
+
+  if (c == '\\' && (syntax & RE_BACKSLASH_ESCAPE_IN_LISTS)
+      && re_string_cur_idx (input) + 1 < re_string_length (input))
+    {
+      /* In this case, '\' escape a character.  */
+      unsigned char c2;
+      re_string_skip_bytes (input, 1);
+      c2 = re_string_peek_byte (input, 0);
+      token->opr.c = c2;
+      token->type = CHARACTER;
+      return 1;
+    }
+  if (c == '[') /* '[' is a special char in a bracket exps.  */
+    {
+      unsigned char c2;
+      int token_len;
+      if (re_string_cur_idx (input) + 1 < re_string_length (input))
+	c2 = re_string_peek_byte (input, 1);
+      else
+	c2 = 0;
+      token->opr.c = c2;
+      token_len = 2;
+      switch (c2)
+	{
+	case '.':
+	  token->type = OP_OPEN_COLL_ELEM;
+	  break;
+
+	case '=':
+	  token->type = OP_OPEN_EQUIV_CLASS;
+	  break;
+
+	case ':':
+	  if (syntax & RE_CHAR_CLASSES)
+	    {
+	      token->type = OP_OPEN_CHAR_CLASS;
+	      break;
+	    }
+	  FALLTHROUGH;
+	default:
+	  token->type = CHARACTER;
+	  token->opr.c = c;
+	  token_len = 1;
+	  break;
+	}
+      return token_len;
+    }
+  switch (c)
+    {
+    case '-':
+      token->type = OP_CHARSET_RANGE;
+      break;
+    case ']':
+      token->type = OP_CLOSE_BRACKET;
+      break;
+    case '^':
+      token->type = OP_NON_MATCH_LIST;
+      break;
+    default:
+      token->type = CHARACTER;
+    }
+  return 1;
+}
+
+/* Functions for parser.  */
+
+/* Entry point of the parser.
+   Parse the regular expression REGEXP and return the structure tree.
+   If an error occurs, ERR is set by error code, and return NULL.
+   This function build the following tree, from regular expression <reg_exp>:
+	   CAT
+	   / \
+	  /   \
+   <reg_exp>  EOR
+
+   CAT means concatenation.
+   EOR means end of regular expression.  */
+
+static bin_tree_t *
+parse (re_string_t *regexp, regex_t *preg, reg_syntax_t syntax,
+       reg_errcode_t *err)
+{
+  re_dfa_t *dfa = preg->buffer;
+  bin_tree_t *tree, *eor, *root;
+  re_token_t current_token;
+  dfa->syntax = syntax;
+  fetch_token (&current_token, regexp, syntax | RE_CARET_ANCHORS_HERE);
+  tree = parse_reg_exp (regexp, preg, &current_token, syntax, 0, err);
+  if (BE (*err != REG_NOERROR && tree == NULL, 0))
+    return NULL;
+  eor = create_tree (dfa, NULL, NULL, END_OF_RE);
+  if (tree != NULL)
+    root = create_tree (dfa, tree, eor, CONCAT);
+  else
+    root = eor;
+  if (BE (eor == NULL || root == NULL, 0))
+    {
+      *err = REG_ESPACE;
+      return NULL;
+    }
+  return root;
+}
+
+/* This function build the following tree, from regular expression
+   <branch1>|<branch2>:
+	   ALT
+	   / \
+	  /   \
+   <branch1> <branch2>
+
+   ALT means alternative, which represents the operator '|'.  */
+
+static bin_tree_t *
+parse_reg_exp (re_string_t *regexp, regex_t *preg, re_token_t *token,
+	       reg_syntax_t syntax, Idx nest, reg_errcode_t *err)
+{
+  re_dfa_t *dfa = preg->buffer;
+  bin_tree_t *tree, *branch = NULL;
+  bitset_word_t initial_bkref_map = dfa->completed_bkref_map;
+  tree = parse_branch (regexp, preg, token, syntax, nest, err);
+  if (BE (*err != REG_NOERROR && tree == NULL, 0))
+    return NULL;
+
+  while (token->type == OP_ALT)
+    {
+      fetch_token (token, regexp, syntax | RE_CARET_ANCHORS_HERE);
+      if (token->type != OP_ALT && token->type != END_OF_RE
+	  && (nest == 0 || token->type != OP_CLOSE_SUBEXP))
+	{
+	  bitset_word_t accumulated_bkref_map = dfa->completed_bkref_map;
+	  dfa->completed_bkref_map = initial_bkref_map;
+	  branch = parse_branch (regexp, preg, token, syntax, nest, err);
+	  if (BE (*err != REG_NOERROR && branch == NULL, 0))
+	    {
+	      if (tree != NULL)
+		postorder (tree, free_tree, NULL);
+	      return NULL;
+	    }
+	  dfa->completed_bkref_map |= accumulated_bkref_map;
+	}
+      else
+	branch = NULL;
+      tree = create_tree (dfa, tree, branch, OP_ALT);
+      if (BE (tree == NULL, 0))
+	{
+	  *err = REG_ESPACE;
+	  return NULL;
+	}
+    }
+  return tree;
+}
+
+/* This function build the following tree, from regular expression
+   <exp1><exp2>:
+	CAT
+	/ \
+       /   \
+   <exp1> <exp2>
+
+   CAT means concatenation.  */
+
+static bin_tree_t *
+parse_branch (re_string_t *regexp, regex_t *preg, re_token_t *token,
+	      reg_syntax_t syntax, Idx nest, reg_errcode_t *err)
+{
+  bin_tree_t *tree, *expr;
+  re_dfa_t *dfa = preg->buffer;
+  tree = parse_expression (regexp, preg, token, syntax, nest, err);
+  if (BE (*err != REG_NOERROR && tree == NULL, 0))
+    return NULL;
+
+  while (token->type != OP_ALT && token->type != END_OF_RE
+	 && (nest == 0 || token->type != OP_CLOSE_SUBEXP))
+    {
+      expr = parse_expression (regexp, preg, token, syntax, nest, err);
+      if (BE (*err != REG_NOERROR && expr == NULL, 0))
+	{
+	  if (tree != NULL)
+	    postorder (tree, free_tree, NULL);
+	  return NULL;
+	}
+      if (tree != NULL && expr != NULL)
+	{
+	  bin_tree_t *newtree = create_tree (dfa, tree, expr, CONCAT);
+	  if (newtree == NULL)
+	    {
+	      postorder (expr, free_tree, NULL);
+	      postorder (tree, free_tree, NULL);
+	      *err = REG_ESPACE;
+	      return NULL;
+	    }
+	  tree = newtree;
+	}
+      else if (tree == NULL)
+	tree = expr;
+      /* Otherwise expr == NULL, we don't need to create new tree.  */
+    }
+  return tree;
+}
+
+/* This function build the following tree, from regular expression a*:
+	 *
+	 |
+	 a
+*/
+
+static bin_tree_t *
+parse_expression (re_string_t *regexp, regex_t *preg, re_token_t *token,
+		  reg_syntax_t syntax, Idx nest, reg_errcode_t *err)
+{
+  re_dfa_t *dfa = preg->buffer;
+  bin_tree_t *tree;
+  switch (token->type)
+    {
+    case CHARACTER:
+      tree = create_token_tree (dfa, NULL, NULL, token);
+      if (BE (tree == NULL, 0))
+	{
+	  *err = REG_ESPACE;
+	  return NULL;
+	}
+#ifdef RE_ENABLE_I18N
+      if (dfa->mb_cur_max > 1)
+	{
+	  while (!re_string_eoi (regexp)
+		 && !re_string_first_byte (regexp, re_string_cur_idx (regexp)))
+	    {
+	      bin_tree_t *mbc_remain;
+	      fetch_token (token, regexp, syntax);
+	      mbc_remain = create_token_tree (dfa, NULL, NULL, token);
+	      tree = create_tree (dfa, tree, mbc_remain, CONCAT);
+	      if (BE (mbc_remain == NULL || tree == NULL, 0))
+		{
+		  *err = REG_ESPACE;
+		  return NULL;
+		}
+	    }
+	}
+#endif
+      break;
+
+    case OP_OPEN_SUBEXP:
+      tree = parse_sub_exp (regexp, preg, token, syntax, nest + 1, err);
+      if (BE (*err != REG_NOERROR && tree == NULL, 0))
+	return NULL;
+      break;
+
+    case OP_OPEN_BRACKET:
+      tree = parse_bracket_exp (regexp, dfa, token, syntax, err);
+      if (BE (*err != REG_NOERROR && tree == NULL, 0))
+	return NULL;
+      break;
+
+    case OP_BACK_REF:
+      if (!BE (dfa->completed_bkref_map & (1 << token->opr.idx), 1))
+	{
+	  *err = REG_ESUBREG;
+	  return NULL;
+	}
+      dfa->used_bkref_map |= 1 << token->opr.idx;
+      tree = create_token_tree (dfa, NULL, NULL, token);
+      if (BE (tree == NULL, 0))
+	{
+	  *err = REG_ESPACE;
+	  return NULL;
+	}
+      ++dfa->nbackref;
+      dfa->has_mb_node = 1;
+      break;
+
+    case OP_OPEN_DUP_NUM:
+      if (syntax & RE_CONTEXT_INVALID_DUP)
+	{
+	  *err = REG_BADRPT;
+	  return NULL;
+	}
+      FALLTHROUGH;
+    case OP_DUP_ASTERISK:
+    case OP_DUP_PLUS:
+    case OP_DUP_QUESTION:
+      if (syntax & RE_CONTEXT_INVALID_OPS)
+	{
+	  *err = REG_BADRPT;
+	  return NULL;
+	}
+      else if (syntax & RE_CONTEXT_INDEP_OPS)
+	{
+	  fetch_token (token, regexp, syntax);
+	  return parse_expression (regexp, preg, token, syntax, nest, err);
+	}
+      FALLTHROUGH;
+    case OP_CLOSE_SUBEXP:
+      if ((token->type == OP_CLOSE_SUBEXP) &&
+	  !(syntax & RE_UNMATCHED_RIGHT_PAREN_ORD))
+	{
+	  *err = REG_ERPAREN;
+	  return NULL;
+	}
+      FALLTHROUGH;
+    case OP_CLOSE_DUP_NUM:
+      /* We treat it as a normal character.  */
+
+      /* Then we can these characters as normal characters.  */
+      token->type = CHARACTER;
+      /* mb_partial and word_char bits should be initialized already
+	 by peek_token.  */
+      tree = create_token_tree (dfa, NULL, NULL, token);
+      if (BE (tree == NULL, 0))
+	{
+	  *err = REG_ESPACE;
+	  return NULL;
+	}
+      break;
+
+    case ANCHOR:
+      if ((token->opr.ctx_type
+	   & (WORD_DELIM | NOT_WORD_DELIM | WORD_FIRST | WORD_LAST))
+	  && dfa->word_ops_used == 0)
+	init_word_char (dfa);
+      if (token->opr.ctx_type == WORD_DELIM
+	  || token->opr.ctx_type == NOT_WORD_DELIM)
+	{
+	  bin_tree_t *tree_first, *tree_last;
+	  if (token->opr.ctx_type == WORD_DELIM)
+	    {
+	      token->opr.ctx_type = WORD_FIRST;
+	      tree_first = create_token_tree (dfa, NULL, NULL, token);
+	      token->opr.ctx_type = WORD_LAST;
+	    }
+	  else
+	    {
+	      token->opr.ctx_type = INSIDE_WORD;
+	      tree_first = create_token_tree (dfa, NULL, NULL, token);
+	      token->opr.ctx_type = INSIDE_NOTWORD;
+	    }
+	  tree_last = create_token_tree (dfa, NULL, NULL, token);
+	  tree = create_tree (dfa, tree_first, tree_last, OP_ALT);
+	  if (BE (tree_first == NULL || tree_last == NULL || tree == NULL, 0))
+	    {
+	      *err = REG_ESPACE;
+	      return NULL;
+	    }
+	}
+      else
+	{
+	  tree = create_token_tree (dfa, NULL, NULL, token);
+	  if (BE (tree == NULL, 0))
+	    {
+	      *err = REG_ESPACE;
+	      return NULL;
+	    }
+	}
+      /* We must return here, since ANCHORs can't be followed
+	 by repetition operators.
+	 eg. RE"^*" is invalid or "<ANCHOR(^)><CHAR(*)>",
+	     it must not be "<ANCHOR(^)><REPEAT(*)>".  */
+      fetch_token (token, regexp, syntax);
+      return tree;
+
+    case OP_PERIOD:
+      tree = create_token_tree (dfa, NULL, NULL, token);
+      if (BE (tree == NULL, 0))
+	{
+	  *err = REG_ESPACE;
+	  return NULL;
+	}
+      if (dfa->mb_cur_max > 1)
+	dfa->has_mb_node = 1;
+      break;
+
+    case OP_WORD:
+    case OP_NOTWORD:
+      tree = build_charclass_op (dfa, regexp->trans,
+				 "alnum",
+				 "_",
+				 token->type == OP_NOTWORD, err);
+      if (BE (*err != REG_NOERROR && tree == NULL, 0))
+	return NULL;
+      break;
+
+    case OP_SPACE:
+    case OP_NOTSPACE:
+      tree = build_charclass_op (dfa, regexp->trans,
+				 "space",
+				 "",
+				 token->type == OP_NOTSPACE, err);
+      if (BE (*err != REG_NOERROR && tree == NULL, 0))
+	return NULL;
+      break;
+
+    case OP_ALT:
+    case END_OF_RE:
+      return NULL;
+
+    case BACK_SLASH:
+      *err = REG_EESCAPE;
+      return NULL;
+
+    default:
+      /* Must not happen?  */
+#ifdef DEBUG
+      assert (0);
+#endif
+      return NULL;
+    }
+  fetch_token (token, regexp, syntax);
+
+  while (token->type == OP_DUP_ASTERISK || token->type == OP_DUP_PLUS
+	 || token->type == OP_DUP_QUESTION || token->type == OP_OPEN_DUP_NUM)
+    {
+      bin_tree_t *dup_tree = parse_dup_op (tree, regexp, dfa, token,
+					   syntax, err);
+      if (BE (*err != REG_NOERROR && dup_tree == NULL, 0))
+	{
+	  if (tree != NULL)
+	    postorder (tree, free_tree, NULL);
+	  return NULL;
+	}
+      tree = dup_tree;
+      /* In BRE consecutive duplications are not allowed.  */
+      if ((syntax & RE_CONTEXT_INVALID_DUP)
+	  && (token->type == OP_DUP_ASTERISK
+	      || token->type == OP_OPEN_DUP_NUM))
+	{
+	  if (tree != NULL)
+	    postorder (tree, free_tree, NULL);
+	  *err = REG_BADRPT;
+	  return NULL;
+	}
+    }
+
+  return tree;
+}
+
+/* This function build the following tree, from regular expression
+   (<reg_exp>):
+	 SUBEXP
+	    |
+	<reg_exp>
+*/
+
+static bin_tree_t *
+parse_sub_exp (re_string_t *regexp, regex_t *preg, re_token_t *token,
+	       reg_syntax_t syntax, Idx nest, reg_errcode_t *err)
+{
+  re_dfa_t *dfa = preg->buffer;
+  bin_tree_t *tree;
+  size_t cur_nsub;
+  cur_nsub = preg->re_nsub++;
+
+  fetch_token (token, regexp, syntax | RE_CARET_ANCHORS_HERE);
+
+  /* The subexpression may be a null string.  */
+  if (token->type == OP_CLOSE_SUBEXP)
+    tree = NULL;
+  else
+    {
+      tree = parse_reg_exp (regexp, preg, token, syntax, nest, err);
+      if (BE (*err == REG_NOERROR && token->type != OP_CLOSE_SUBEXP, 0))
+	{
+	  if (tree != NULL)
+	    postorder (tree, free_tree, NULL);
+	  *err = REG_EPAREN;
+	}
+      if (BE (*err != REG_NOERROR, 0))
+	return NULL;
+    }
+
+  if (cur_nsub <= '9' - '1')
+    dfa->completed_bkref_map |= 1 << cur_nsub;
+
+  tree = create_tree (dfa, tree, NULL, SUBEXP);
+  if (BE (tree == NULL, 0))
+    {
+      *err = REG_ESPACE;
+      return NULL;
+    }
+  tree->token.opr.idx = cur_nsub;
+  return tree;
+}
+
+/* This function parse repetition operators like "*", "+", "{1,3}" etc.  */
+
+static bin_tree_t *
+parse_dup_op (bin_tree_t *elem, re_string_t *regexp, re_dfa_t *dfa,
+	      re_token_t *token, reg_syntax_t syntax, reg_errcode_t *err)
+{
+  bin_tree_t *tree = NULL, *old_tree = NULL;
+  Idx i, start, end, start_idx = re_string_cur_idx (regexp);
+  re_token_t start_token = *token;
+
+  if (token->type == OP_OPEN_DUP_NUM)
+    {
+      end = 0;
+      start = fetch_number (regexp, token, syntax);
+      if (start == -1)
+	{
+	  if (token->type == CHARACTER && token->opr.c == ',')
+	    start = 0; /* We treat "{,m}" as "{0,m}".  */
+	  else
+	    {
+	      *err = REG_BADBR; /* <re>{} is invalid.  */
+	      return NULL;
+	    }
+	}
+      if (BE (start != -2, 1))
+	{
+	  /* We treat "{n}" as "{n,n}".  */
+	  end = ((token->type == OP_CLOSE_DUP_NUM) ? start
+		 : ((token->type == CHARACTER && token->opr.c == ',')
+		    ? fetch_number (regexp, token, syntax) : -2));
+	}
+      if (BE (start == -2 || end == -2, 0))
+	{
+	  /* Invalid sequence.  */
+	  if (BE (!(syntax & RE_INVALID_INTERVAL_ORD), 0))
+	    {
+	      if (token->type == END_OF_RE)
+		*err = REG_EBRACE;
+	      else
+		*err = REG_BADBR;
+
+	      return NULL;
+	    }
+
+	  /* If the syntax bit is set, rollback.  */
+	  re_string_set_index (regexp, start_idx);
+	  *token = start_token;
+	  token->type = CHARACTER;
+	  /* mb_partial and word_char bits should be already initialized by
+	     peek_token.  */
+	  return elem;
+	}
+
+      if (BE ((end != -1 && start > end)
+	      || token->type != OP_CLOSE_DUP_NUM, 0))
+	{
+	  /* First number greater than second.  */
+	  *err = REG_BADBR;
+	  return NULL;
+	}
+
+      if (BE (RE_DUP_MAX < (end == -1 ? start : end), 0))
+	{
+	  *err = REG_ESIZE;
+	  return NULL;
+	}
+    }
+  else
+    {
+      start = (token->type == OP_DUP_PLUS) ? 1 : 0;
+      end = (token->type == OP_DUP_QUESTION) ? 1 : -1;
+    }
+
+  fetch_token (token, regexp, syntax);
+
+  if (BE (elem == NULL, 0))
+    return NULL;
+  if (BE (start == 0 && end == 0, 0))
+    {
+      postorder (elem, free_tree, NULL);
+      return NULL;
+    }
+
+  /* Extract "<re>{n,m}" to "<re><re>...<re><re>{0,<m-n>}".  */
+  if (BE (start > 0, 0))
+    {
+      tree = elem;
+      for (i = 2; i <= start; ++i)
+	{
+	  elem = duplicate_tree (elem, dfa);
+	  tree = create_tree (dfa, tree, elem, CONCAT);
+	  if (BE (elem == NULL || tree == NULL, 0))
+	    goto parse_dup_op_espace;
+	}
+
+      if (start == end)
+	return tree;
+
+      /* Duplicate ELEM before it is marked optional.  */
+      elem = duplicate_tree (elem, dfa);
+      if (BE (elem == NULL, 0))
+        goto parse_dup_op_espace;
+      old_tree = tree;
+    }
+  else
+    old_tree = NULL;
+
+  if (elem->token.type == SUBEXP)
+    {
+      uintptr_t subidx = elem->token.opr.idx;
+      postorder (elem, mark_opt_subexp, (void *) subidx);
+    }
+
+  tree = create_tree (dfa, elem, NULL,
+		      (end == -1 ? OP_DUP_ASTERISK : OP_ALT));
+  if (BE (tree == NULL, 0))
+    goto parse_dup_op_espace;
+
+  /* This loop is actually executed only when end != -1,
+     to rewrite <re>{0,n} as (<re>(<re>...<re>?)?)?...  We have
+     already created the start+1-th copy.  */
+  if (TYPE_SIGNED (Idx) || end != -1)
+    for (i = start + 2; i <= end; ++i)
+      {
+	elem = duplicate_tree (elem, dfa);
+	tree = create_tree (dfa, tree, elem, CONCAT);
+	if (BE (elem == NULL || tree == NULL, 0))
+	  goto parse_dup_op_espace;
+
+	tree = create_tree (dfa, tree, NULL, OP_ALT);
+	if (BE (tree == NULL, 0))
+	  goto parse_dup_op_espace;
+      }
+
+  if (old_tree)
+    tree = create_tree (dfa, old_tree, tree, CONCAT);
+
+  return tree;
+
+ parse_dup_op_espace:
+  *err = REG_ESPACE;
+  return NULL;
+}
+
+/* Size of the names for collating symbol/equivalence_class/character_class.
+   I'm not sure, but maybe enough.  */
+#define BRACKET_NAME_BUF_SIZE 32
+
+#ifndef _LIBC
+
+# ifdef RE_ENABLE_I18N
+/* Convert the byte B to the corresponding wide character.  In a
+   unibyte locale, treat B as itself if it is an encoding error.
+   In a multibyte locale, return WEOF if B is an encoding error.  */
+static wint_t
+parse_byte (unsigned char b, re_charset_t *mbcset)
+{
+  wint_t wc = __btowc (b);
+  return wc == WEOF && !mbcset ? b : wc;
+}
+#endif
+
+  /* Local function for parse_bracket_exp only used in case of NOT _LIBC.
+     Build the range expression which starts from START_ELEM, and ends
+     at END_ELEM.  The result are written to MBCSET and SBCSET.
+     RANGE_ALLOC is the allocated size of mbcset->range_starts, and
+     mbcset->range_ends, is a pointer argument since we may
+     update it.  */
+
+static reg_errcode_t
+# ifdef RE_ENABLE_I18N
+build_range_exp (const reg_syntax_t syntax,
+                 bitset_t sbcset,
+                 re_charset_t *mbcset,
+                 Idx *range_alloc,
+                 const bracket_elem_t *start_elem,
+                 const bracket_elem_t *end_elem)
+# else /* not RE_ENABLE_I18N */
+build_range_exp (const reg_syntax_t syntax,
+                 bitset_t sbcset,
+                 const bracket_elem_t *start_elem,
+                 const bracket_elem_t *end_elem)
+# endif /* not RE_ENABLE_I18N */
+{
+  unsigned int start_ch, end_ch;
+  /* Equivalence Classes and Character Classes can't be a range start/end.  */
+  if (BE (start_elem->type == EQUIV_CLASS || start_elem->type == CHAR_CLASS
+	  || end_elem->type == EQUIV_CLASS || end_elem->type == CHAR_CLASS,
+	  0))
+    return REG_ERANGE;
+
+  /* We can handle no multi character collating elements without libc
+     support.  */
+  if (BE ((start_elem->type == COLL_SYM
+	   && strlen ((char *) start_elem->opr.name) > 1)
+	  || (end_elem->type == COLL_SYM
+	      && strlen ((char *) end_elem->opr.name) > 1), 0))
+    return REG_ECOLLATE;
+
+# ifdef RE_ENABLE_I18N
+  {
+    wchar_t wc;
+    wint_t start_wc;
+    wint_t end_wc;
+
+    start_ch = ((start_elem->type == SB_CHAR) ? start_elem->opr.ch
+		: ((start_elem->type == COLL_SYM) ? start_elem->opr.name[0]
+		   : 0));
+    end_ch = ((end_elem->type == SB_CHAR) ? end_elem->opr.ch
+	      : ((end_elem->type == COLL_SYM) ? end_elem->opr.name[0]
+		 : 0));
+    start_wc = ((start_elem->type == SB_CHAR || start_elem->type == COLL_SYM)
+		? parse_byte (start_ch, mbcset) : start_elem->opr.wch);
+    end_wc = ((end_elem->type == SB_CHAR || end_elem->type == COLL_SYM)
+	      ? parse_byte (end_ch, mbcset) : end_elem->opr.wch);
+    if (start_wc == WEOF || end_wc == WEOF)
+      return REG_ECOLLATE;
+    else if (BE ((syntax & RE_NO_EMPTY_RANGES) && start_wc > end_wc, 0))
+      return REG_ERANGE;
+
+    /* Got valid collation sequence values, add them as a new entry.
+       However, for !_LIBC we have no collation elements: if the
+       character set is single byte, the single byte character set
+       that we build below suffices.  parse_bracket_exp passes
+       no MBCSET if dfa->mb_cur_max == 1.  */
+    if (mbcset)
+      {
+	/* Check the space of the arrays.  */
+	if (BE (*range_alloc == mbcset->nranges, 0))
+	  {
+	    /* There is not enough space, need realloc.  */
+	    wchar_t *new_array_start, *new_array_end;
+	    Idx new_nranges;
+
+	    /* +1 in case of mbcset->nranges is 0.  */
+	    new_nranges = 2 * mbcset->nranges + 1;
+	    /* Use realloc since mbcset->range_starts and mbcset->range_ends
+	       are NULL if *range_alloc == 0.  */
+	    new_array_start = re_realloc (mbcset->range_starts, wchar_t,
+					  new_nranges);
+	    new_array_end = re_realloc (mbcset->range_ends, wchar_t,
+					new_nranges);
+
+	    if (BE (new_array_start == NULL || new_array_end == NULL, 0))
+	      {
+		re_free (new_array_start);
+		re_free (new_array_end);
+		return REG_ESPACE;
+	      }
+
+	    mbcset->range_starts = new_array_start;
+	    mbcset->range_ends = new_array_end;
+	    *range_alloc = new_nranges;
+	  }
+
+	mbcset->range_starts[mbcset->nranges] = start_wc;
+	mbcset->range_ends[mbcset->nranges++] = end_wc;
+      }
+
+    /* Build the table for single byte characters.  */
+    for (wc = 0; wc < SBC_MAX; ++wc)
+      {
+	if (start_wc <= wc && wc <= end_wc)
+	  bitset_set (sbcset, wc);
+      }
+  }
+# else /* not RE_ENABLE_I18N */
+  {
+    unsigned int ch;
+    start_ch = ((start_elem->type == SB_CHAR ) ? start_elem->opr.ch
+		: ((start_elem->type == COLL_SYM) ? start_elem->opr.name[0]
+		   : 0));
+    end_ch = ((end_elem->type == SB_CHAR ) ? end_elem->opr.ch
+	      : ((end_elem->type == COLL_SYM) ? end_elem->opr.name[0]
+		 : 0));
+    if (start_ch > end_ch)
+      return REG_ERANGE;
+    /* Build the table for single byte characters.  */
+    for (ch = 0; ch < SBC_MAX; ++ch)
+      if (start_ch <= ch  && ch <= end_ch)
+	bitset_set (sbcset, ch);
+  }
+# endif /* not RE_ENABLE_I18N */
+  return REG_NOERROR;
+}
+#endif /* not _LIBC */
+
+#ifndef _LIBC
+/* Helper function for parse_bracket_exp only used in case of NOT _LIBC..
+   Build the collating element which is represented by NAME.
+   The result are written to MBCSET and SBCSET.
+   COLL_SYM_ALLOC is the allocated size of mbcset->coll_sym, is a
+   pointer argument since we may update it.  */
+
+static reg_errcode_t
+# ifdef RE_ENABLE_I18N
+build_collating_symbol (bitset_t sbcset, re_charset_t *mbcset,
+			Idx *coll_sym_alloc, const unsigned char *name)
+# else /* not RE_ENABLE_I18N */
+build_collating_symbol (bitset_t sbcset, const unsigned char *name)
+# endif /* not RE_ENABLE_I18N */
+{
+  size_t name_len = strlen ((const char *) name);
+  if (BE (name_len != 1, 0))
+    return REG_ECOLLATE;
+  else
+    {
+      bitset_set (sbcset, name[0]);
+      return REG_NOERROR;
+    }
+}
+#endif /* not _LIBC */
+
+/* This function parse bracket expression like "[abc]", "[a-c]",
+   "[[.a-a.]]" etc.  */
+
+static bin_tree_t *
+parse_bracket_exp (re_string_t *regexp, re_dfa_t *dfa, re_token_t *token,
+		   reg_syntax_t syntax, reg_errcode_t *err)
+{
+#ifdef _LIBC
+  const unsigned char *collseqmb;
+  const char *collseqwc;
+  uint32_t nrules;
+  int32_t table_size;
+  const int32_t *symb_table;
+  const unsigned char *extra;
+
+  /* Local function for parse_bracket_exp used in _LIBC environment.
+     Seek the collating symbol entry corresponding to NAME.
+     Return the index of the symbol in the SYMB_TABLE,
+     or -1 if not found.  */
+
+  auto inline int32_t
+  __attribute__ ((always_inline))
+  seek_collating_symbol_entry (const unsigned char *name, size_t name_len)
+    {
+      int32_t elem;
+
+      for (elem = 0; elem < table_size; elem++)
+	if (symb_table[2 * elem] != 0)
+	  {
+	    int32_t idx = symb_table[2 * elem + 1];
+	    /* Skip the name of collating element name.  */
+	    idx += 1 + extra[idx];
+	    if (/* Compare the length of the name.  */
+		name_len == extra[idx]
+		/* Compare the name.  */
+		&& memcmp (name, &extra[idx + 1], name_len) == 0)
+	      /* Yep, this is the entry.  */
+	      return elem;
+	  }
+      return -1;
+    }
+
+  /* Local function for parse_bracket_exp used in _LIBC environment.
+     Look up the collation sequence value of BR_ELEM.
+     Return the value if succeeded, UINT_MAX otherwise.  */
+
+  auto inline unsigned int
+  __attribute__ ((always_inline))
+  lookup_collation_sequence_value (bracket_elem_t *br_elem)
+    {
+      if (br_elem->type == SB_CHAR)
+	{
+	  /*
+	  if (MB_CUR_MAX == 1)
+	  */
+	  if (nrules == 0)
+	    return collseqmb[br_elem->opr.ch];
+	  else
+	    {
+	      wint_t wc = __btowc (br_elem->opr.ch);
+	      return __collseq_table_lookup (collseqwc, wc);
+	    }
+	}
+      else if (br_elem->type == MB_CHAR)
+	{
+	  if (nrules != 0)
+	    return __collseq_table_lookup (collseqwc, br_elem->opr.wch);
+	}
+      else if (br_elem->type == COLL_SYM)
+	{
+	  size_t sym_name_len = strlen ((char *) br_elem->opr.name);
+	  if (nrules != 0)
+	    {
+	      int32_t elem, idx;
+	      elem = seek_collating_symbol_entry (br_elem->opr.name,
+						  sym_name_len);
+	      if (elem != -1)
+		{
+		  /* We found the entry.  */
+		  idx = symb_table[2 * elem + 1];
+		  /* Skip the name of collating element name.  */
+		  idx += 1 + extra[idx];
+		  /* Skip the byte sequence of the collating element.  */
+		  idx += 1 + extra[idx];
+		  /* Adjust for the alignment.  */
+		  idx = (idx + 3) & ~3;
+		  /* Skip the multibyte collation sequence value.  */
+		  idx += sizeof (unsigned int);
+		  /* Skip the wide char sequence of the collating element.  */
+		  idx += sizeof (unsigned int) *
+		    (1 + *(unsigned int *) (extra + idx));
+		  /* Return the collation sequence value.  */
+		  return *(unsigned int *) (extra + idx);
+		}
+	      else if (sym_name_len == 1)
+		{
+		  /* No valid character.  Match it as a single byte
+		     character.  */
+		  return collseqmb[br_elem->opr.name[0]];
+		}
+	    }
+	  else if (sym_name_len == 1)
+	    return collseqmb[br_elem->opr.name[0]];
+	}
+      return UINT_MAX;
+    }
+
+  /* Local function for parse_bracket_exp used in _LIBC environment.
+     Build the range expression which starts from START_ELEM, and ends
+     at END_ELEM.  The result are written to MBCSET and SBCSET.
+     RANGE_ALLOC is the allocated size of mbcset->range_starts, and
+     mbcset->range_ends, is a pointer argument since we may
+     update it.  */
+
+  auto inline reg_errcode_t
+  __attribute__ ((always_inline))
+  build_range_exp (bitset_t sbcset, re_charset_t *mbcset, int *range_alloc,
+		   bracket_elem_t *start_elem, bracket_elem_t *end_elem)
+    {
+      unsigned int ch;
+      uint32_t start_collseq;
+      uint32_t end_collseq;
+
+      /* Equivalence Classes and Character Classes can't be a range
+	 start/end.  */
+      if (BE (start_elem->type == EQUIV_CLASS || start_elem->type == CHAR_CLASS
+	      || end_elem->type == EQUIV_CLASS || end_elem->type == CHAR_CLASS,
+	      0))
+	return REG_ERANGE;
+
+      /* FIXME: Implement rational ranges here, too.  */
+      start_collseq = lookup_collation_sequence_value (start_elem);
+      end_collseq = lookup_collation_sequence_value (end_elem);
+      /* Check start/end collation sequence values.  */
+      if (BE (start_collseq == UINT_MAX || end_collseq == UINT_MAX, 0))
+	return REG_ECOLLATE;
+      if (BE ((syntax & RE_NO_EMPTY_RANGES) && start_collseq > end_collseq, 0))
+	return REG_ERANGE;
+
+      /* Got valid collation sequence values, add them as a new entry.
+	 However, if we have no collation elements, and the character set
+	 is single byte, the single byte character set that we
+	 build below suffices. */
+      if (nrules > 0 || dfa->mb_cur_max > 1)
+	{
+	  /* Check the space of the arrays.  */
+	  if (BE (*range_alloc == mbcset->nranges, 0))
+	    {
+	      /* There is not enough space, need realloc.  */
+	      uint32_t *new_array_start;
+	      uint32_t *new_array_end;
+	      Idx new_nranges;
+
+	      /* +1 in case of mbcset->nranges is 0.  */
+	      new_nranges = 2 * mbcset->nranges + 1;
+	      new_array_start = re_realloc (mbcset->range_starts, uint32_t,
+					    new_nranges);
+	      new_array_end = re_realloc (mbcset->range_ends, uint32_t,
+					  new_nranges);
+
+	      if (BE (new_array_start == NULL || new_array_end == NULL, 0))
+		return REG_ESPACE;
+
+	      mbcset->range_starts = new_array_start;
+	      mbcset->range_ends = new_array_end;
+	      *range_alloc = new_nranges;
+	    }
+
+	  mbcset->range_starts[mbcset->nranges] = start_collseq;
+	  mbcset->range_ends[mbcset->nranges++] = end_collseq;
+	}
+
+      /* Build the table for single byte characters.  */
+      for (ch = 0; ch < SBC_MAX; ch++)
+	{
+	  uint32_t ch_collseq;
+	  /*
+	  if (MB_CUR_MAX == 1)
+	  */
+	  if (nrules == 0)
+	    ch_collseq = collseqmb[ch];
+	  else
+	    ch_collseq = __collseq_table_lookup (collseqwc, __btowc (ch));
+	  if (start_collseq <= ch_collseq && ch_collseq <= end_collseq)
+	    bitset_set (sbcset, ch);
+	}
+      return REG_NOERROR;
+    }
+
+  /* Local function for parse_bracket_exp used in _LIBC environment.
+     Build the collating element which is represented by NAME.
+     The result are written to MBCSET and SBCSET.
+     COLL_SYM_ALLOC is the allocated size of mbcset->coll_sym, is a
+     pointer argument since we may update it.  */
+
+  auto inline reg_errcode_t
+  __attribute__ ((always_inline))
+  build_collating_symbol (bitset_t sbcset, re_charset_t *mbcset,
+			  Idx *coll_sym_alloc, const unsigned char *name)
+    {
+      int32_t elem, idx;
+      size_t name_len = strlen ((const char *) name);
+      if (nrules != 0)
+	{
+	  elem = seek_collating_symbol_entry (name, name_len);
+	  if (elem != -1)
+	    {
+	      /* We found the entry.  */
+	      idx = symb_table[2 * elem + 1];
+	      /* Skip the name of collating element name.  */
+	      idx += 1 + extra[idx];
+	    }
+	  else if (name_len == 1)
+	    {
+	      /* No valid character, treat it as a normal
+		 character.  */
+	      bitset_set (sbcset, name[0]);
+	      return REG_NOERROR;
+	    }
+	  else
+	    return REG_ECOLLATE;
+
+	  /* Got valid collation sequence, add it as a new entry.  */
+	  /* Check the space of the arrays.  */
+	  if (BE (*coll_sym_alloc == mbcset->ncoll_syms, 0))
+	    {
+	      /* Not enough, realloc it.  */
+	      /* +1 in case of mbcset->ncoll_syms is 0.  */
+	      Idx new_coll_sym_alloc = 2 * mbcset->ncoll_syms + 1;
+	      /* Use realloc since mbcset->coll_syms is NULL
+		 if *alloc == 0.  */
+	      int32_t *new_coll_syms = re_realloc (mbcset->coll_syms, int32_t,
+						   new_coll_sym_alloc);
+	      if (BE (new_coll_syms == NULL, 0))
+		return REG_ESPACE;
+	      mbcset->coll_syms = new_coll_syms;
+	      *coll_sym_alloc = new_coll_sym_alloc;
+	    }
+	  mbcset->coll_syms[mbcset->ncoll_syms++] = idx;
+	  return REG_NOERROR;
+	}
+      else
+	{
+	  if (BE (name_len != 1, 0))
+	    return REG_ECOLLATE;
+	  else
+	    {
+	      bitset_set (sbcset, name[0]);
+	      return REG_NOERROR;
+	    }
+	}
+    }
+#endif
+
+  re_token_t br_token;
+  re_bitset_ptr_t sbcset;
+#ifdef RE_ENABLE_I18N
+  re_charset_t *mbcset;
+  Idx coll_sym_alloc = 0, range_alloc = 0, mbchar_alloc = 0;
+  Idx equiv_class_alloc = 0, char_class_alloc = 0;
+#endif /* not RE_ENABLE_I18N */
+  bool non_match = false;
+  bin_tree_t *work_tree;
+  int token_len;
+  bool first_round = true;
+#ifdef _LIBC
+  collseqmb = (const unsigned char *)
+    _NL_CURRENT (LC_COLLATE, _NL_COLLATE_COLLSEQMB);
+  nrules = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES);
+  if (nrules)
+    {
+      /*
+      if (MB_CUR_MAX > 1)
+      */
+      collseqwc = _NL_CURRENT (LC_COLLATE, _NL_COLLATE_COLLSEQWC);
+      table_size = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_SYMB_HASH_SIZEMB);
+      symb_table = (const int32_t *) _NL_CURRENT (LC_COLLATE,
+						  _NL_COLLATE_SYMB_TABLEMB);
+      extra = (const unsigned char *) _NL_CURRENT (LC_COLLATE,
+						   _NL_COLLATE_SYMB_EXTRAMB);
+    }
+#endif
+  sbcset = (re_bitset_ptr_t) calloc (sizeof (bitset_t), 1);
+#ifdef RE_ENABLE_I18N
+  mbcset = (re_charset_t *) calloc (sizeof (re_charset_t), 1);
+#endif /* RE_ENABLE_I18N */
+#ifdef RE_ENABLE_I18N
+  if (BE (sbcset == NULL || mbcset == NULL, 0))
+#else
+  if (BE (sbcset == NULL, 0))
+#endif /* RE_ENABLE_I18N */
+    {
+      re_free (sbcset);
+#ifdef RE_ENABLE_I18N
+      re_free (mbcset);
+#endif
+      *err = REG_ESPACE;
+      return NULL;
+    }
+
+  token_len = peek_token_bracket (token, regexp, syntax);
+  if (BE (token->type == END_OF_RE, 0))
+    {
+      *err = REG_BADPAT;
+      goto parse_bracket_exp_free_return;
+    }
+  if (token->type == OP_NON_MATCH_LIST)
+    {
+#ifdef RE_ENABLE_I18N
+      mbcset->non_match = 1;
+#endif /* not RE_ENABLE_I18N */
+      non_match = true;
+      if (syntax & RE_HAT_LISTS_NOT_NEWLINE)
+	bitset_set (sbcset, '\n');
+      re_string_skip_bytes (regexp, token_len); /* Skip a token.  */
+      token_len = peek_token_bracket (token, regexp, syntax);
+      if (BE (token->type == END_OF_RE, 0))
+	{
+	  *err = REG_BADPAT;
+	  goto parse_bracket_exp_free_return;
+	}
+    }
+
+  /* We treat the first ']' as a normal character.  */
+  if (token->type == OP_CLOSE_BRACKET)
+    token->type = CHARACTER;
+
+  while (1)
+    {
+      bracket_elem_t start_elem, end_elem;
+      unsigned char start_name_buf[BRACKET_NAME_BUF_SIZE];
+      unsigned char end_name_buf[BRACKET_NAME_BUF_SIZE];
+      reg_errcode_t ret;
+      int token_len2 = 0;
+      bool is_range_exp = false;
+      re_token_t token2;
+
+      start_elem.opr.name = start_name_buf;
+      start_elem.type = COLL_SYM;
+      ret = parse_bracket_element (&start_elem, regexp, token, token_len, dfa,
+				   syntax, first_round);
+      if (BE (ret != REG_NOERROR, 0))
+	{
+	  *err = ret;
+	  goto parse_bracket_exp_free_return;
+	}
+      first_round = false;
+
+      /* Get information about the next token.  We need it in any case.  */
+      token_len = peek_token_bracket (token, regexp, syntax);
+
+      /* Do not check for ranges if we know they are not allowed.  */
+      if (start_elem.type != CHAR_CLASS && start_elem.type != EQUIV_CLASS)
+	{
+	  if (BE (token->type == END_OF_RE, 0))
+	    {
+	      *err = REG_EBRACK;
+	      goto parse_bracket_exp_free_return;
+	    }
+	  if (token->type == OP_CHARSET_RANGE)
+	    {
+	      re_string_skip_bytes (regexp, token_len); /* Skip '-'.  */
+	      token_len2 = peek_token_bracket (&token2, regexp, syntax);
+	      if (BE (token2.type == END_OF_RE, 0))
+		{
+		  *err = REG_EBRACK;
+		  goto parse_bracket_exp_free_return;
+		}
+	      if (token2.type == OP_CLOSE_BRACKET)
+		{
+		  /* We treat the last '-' as a normal character.  */
+		  re_string_skip_bytes (regexp, -token_len);
+		  token->type = CHARACTER;
+		}
+	      else
+		is_range_exp = true;
+	    }
+	}
+
+      if (is_range_exp == true)
+	{
+	  end_elem.opr.name = end_name_buf;
+	  end_elem.type = COLL_SYM;
+	  ret = parse_bracket_element (&end_elem, regexp, &token2, token_len2,
+				       dfa, syntax, true);
+	  if (BE (ret != REG_NOERROR, 0))
+	    {
+	      *err = ret;
+	      goto parse_bracket_exp_free_return;
+	    }
+
+	  token_len = peek_token_bracket (token, regexp, syntax);
+
+#ifdef _LIBC
+	  *err = build_range_exp (sbcset, mbcset, &range_alloc,
+				  &start_elem, &end_elem);
+#else
+# ifdef RE_ENABLE_I18N
+	  *err = build_range_exp (syntax, sbcset,
+				  dfa->mb_cur_max > 1 ? mbcset : NULL,
+				  &range_alloc, &start_elem, &end_elem);
+# else
+	  *err = build_range_exp (syntax, sbcset, &start_elem, &end_elem);
+# endif
+#endif /* RE_ENABLE_I18N */
+	  if (BE (*err != REG_NOERROR, 0))
+	    goto parse_bracket_exp_free_return;
+	}
+      else
+	{
+	  switch (start_elem.type)
+	    {
+	    case SB_CHAR:
+	      bitset_set (sbcset, start_elem.opr.ch);
+	      break;
+#ifdef RE_ENABLE_I18N
+	    case MB_CHAR:
+	      /* Check whether the array has enough space.  */
+	      if (BE (mbchar_alloc == mbcset->nmbchars, 0))
+		{
+		  wchar_t *new_mbchars;
+		  /* Not enough, realloc it.  */
+		  /* +1 in case of mbcset->nmbchars is 0.  */
+		  mbchar_alloc = 2 * mbcset->nmbchars + 1;
+		  /* Use realloc since array is NULL if *alloc == 0.  */
+		  new_mbchars = re_realloc (mbcset->mbchars, wchar_t,
+					    mbchar_alloc);
+		  if (BE (new_mbchars == NULL, 0))
+		    goto parse_bracket_exp_espace;
+		  mbcset->mbchars = new_mbchars;
+		}
+	      mbcset->mbchars[mbcset->nmbchars++] = start_elem.opr.wch;
+	      break;
+#endif /* RE_ENABLE_I18N */
+	    case EQUIV_CLASS:
+	      *err = build_equiv_class (sbcset,
+#ifdef RE_ENABLE_I18N
+					mbcset, &equiv_class_alloc,
+#endif /* RE_ENABLE_I18N */
+					start_elem.opr.name);
+	      if (BE (*err != REG_NOERROR, 0))
+		goto parse_bracket_exp_free_return;
+	      break;
+	    case COLL_SYM:
+	      *err = build_collating_symbol (sbcset,
+#ifdef RE_ENABLE_I18N
+					     mbcset, &coll_sym_alloc,
+#endif /* RE_ENABLE_I18N */
+					     start_elem.opr.name);
+	      if (BE (*err != REG_NOERROR, 0))
+		goto parse_bracket_exp_free_return;
+	      break;
+	    case CHAR_CLASS:
+	      *err = build_charclass (regexp->trans, sbcset,
+#ifdef RE_ENABLE_I18N
+				      mbcset, &char_class_alloc,
+#endif /* RE_ENABLE_I18N */
+				      (const char *) start_elem.opr.name,
+				      syntax);
+	      if (BE (*err != REG_NOERROR, 0))
+	       goto parse_bracket_exp_free_return;
+	      break;
+	    default:
+	      assert (0);
+	      break;
+	    }
+	}
+      if (BE (token->type == END_OF_RE, 0))
+	{
+	  *err = REG_EBRACK;
+	  goto parse_bracket_exp_free_return;
+	}
+      if (token->type == OP_CLOSE_BRACKET)
+	break;
+    }
+
+  re_string_skip_bytes (regexp, token_len); /* Skip a token.  */
+
+  /* If it is non-matching list.  */
+  if (non_match)
+    bitset_not (sbcset);
+
+#ifdef RE_ENABLE_I18N
+  /* Ensure only single byte characters are set.  */
+  if (dfa->mb_cur_max > 1)
+    bitset_mask (sbcset, dfa->sb_char);
+
+  if (mbcset->nmbchars || mbcset->ncoll_syms || mbcset->nequiv_classes
+      || mbcset->nranges || (dfa->mb_cur_max > 1 && (mbcset->nchar_classes
+						     || mbcset->non_match)))
+    {
+      bin_tree_t *mbc_tree;
+      int sbc_idx;
+      /* Build a tree for complex bracket.  */
+      dfa->has_mb_node = 1;
+      br_token.type = COMPLEX_BRACKET;
+      br_token.opr.mbcset = mbcset;
+      mbc_tree = create_token_tree (dfa, NULL, NULL, &br_token);
+      if (BE (mbc_tree == NULL, 0))
+	goto parse_bracket_exp_espace;
+      for (sbc_idx = 0; sbc_idx < BITSET_WORDS; ++sbc_idx)
+	if (sbcset[sbc_idx])
+	  break;
+      /* If there are no bits set in sbcset, there is no point
+	 of having both SIMPLE_BRACKET and COMPLEX_BRACKET.  */
+      if (sbc_idx < BITSET_WORDS)
+	{
+	  /* Build a tree for simple bracket.  */
+	  br_token.type = SIMPLE_BRACKET;
+	  br_token.opr.sbcset = sbcset;
+	  work_tree = create_token_tree (dfa, NULL, NULL, &br_token);
+	  if (BE (work_tree == NULL, 0))
+	    goto parse_bracket_exp_espace;
+
+	  /* Then join them by ALT node.  */
+	  work_tree = create_tree (dfa, work_tree, mbc_tree, OP_ALT);
+	  if (BE (work_tree == NULL, 0))
+	    goto parse_bracket_exp_espace;
+	}
+      else
+	{
+	  re_free (sbcset);
+	  work_tree = mbc_tree;
+	}
+    }
+  else
+#endif /* not RE_ENABLE_I18N */
+    {
+#ifdef RE_ENABLE_I18N
+      free_charset (mbcset);
+#endif
+      /* Build a tree for simple bracket.  */
+      br_token.type = SIMPLE_BRACKET;
+      br_token.opr.sbcset = sbcset;
+      work_tree = create_token_tree (dfa, NULL, NULL, &br_token);
+      if (BE (work_tree == NULL, 0))
+	goto parse_bracket_exp_espace;
+    }
+  return work_tree;
+
+ parse_bracket_exp_espace:
+  *err = REG_ESPACE;
+ parse_bracket_exp_free_return:
+  re_free (sbcset);
+#ifdef RE_ENABLE_I18N
+  free_charset (mbcset);
+#endif /* RE_ENABLE_I18N */
+  return NULL;
+}
+
+/* Parse an element in the bracket expression.  */
+
+static reg_errcode_t
+parse_bracket_element (bracket_elem_t *elem, re_string_t *regexp,
+		       re_token_t *token, int token_len, re_dfa_t *dfa,
+		       reg_syntax_t syntax, bool accept_hyphen)
+{
+#ifdef RE_ENABLE_I18N
+  int cur_char_size;
+  cur_char_size = re_string_char_size_at (regexp, re_string_cur_idx (regexp));
+  if (cur_char_size > 1)
+    {
+      elem->type = MB_CHAR;
+      elem->opr.wch = re_string_wchar_at (regexp, re_string_cur_idx (regexp));
+      re_string_skip_bytes (regexp, cur_char_size);
+      return REG_NOERROR;
+    }
+#endif /* RE_ENABLE_I18N */
+  re_string_skip_bytes (regexp, token_len); /* Skip a token.  */
+  if (token->type == OP_OPEN_COLL_ELEM || token->type == OP_OPEN_CHAR_CLASS
+      || token->type == OP_OPEN_EQUIV_CLASS)
+    return parse_bracket_symbol (elem, regexp, token);
+  if (BE (token->type == OP_CHARSET_RANGE, 0) && !accept_hyphen)
+    {
+      /* A '-' must only appear as anything but a range indicator before
+	 the closing bracket.  Everything else is an error.  */
+      re_token_t token2;
+      (void) peek_token_bracket (&token2, regexp, syntax);
+      if (token2.type != OP_CLOSE_BRACKET)
+	/* The actual error value is not standardized since this whole
+	   case is undefined.  But ERANGE makes good sense.  */
+	return REG_ERANGE;
+    }
+  elem->type = SB_CHAR;
+  elem->opr.ch = token->opr.c;
+  return REG_NOERROR;
+}
+
+/* Parse a bracket symbol in the bracket expression.  Bracket symbols are
+   such as [:<character_class>:], [.<collating_element>.], and
+   [=<equivalent_class>=].  */
+
+static reg_errcode_t
+parse_bracket_symbol (bracket_elem_t *elem, re_string_t *regexp,
+		      re_token_t *token)
+{
+  unsigned char ch, delim = token->opr.c;
+  int i = 0;
+  if (re_string_eoi(regexp))
+    return REG_EBRACK;
+  for (;; ++i)
+    {
+      if (i >= BRACKET_NAME_BUF_SIZE)
+	return REG_EBRACK;
+      if (token->type == OP_OPEN_CHAR_CLASS)
+	ch = re_string_fetch_byte_case (regexp);
+      else
+	ch = re_string_fetch_byte (regexp);
+      if (re_string_eoi(regexp))
+	return REG_EBRACK;
+      if (ch == delim && re_string_peek_byte (regexp, 0) == ']')
+	break;
+      elem->opr.name[i] = ch;
+    }
+  re_string_skip_bytes (regexp, 1);
+  elem->opr.name[i] = '\0';
+  switch (token->type)
+    {
+    case OP_OPEN_COLL_ELEM:
+      elem->type = COLL_SYM;
+      break;
+    case OP_OPEN_EQUIV_CLASS:
+      elem->type = EQUIV_CLASS;
+      break;
+    case OP_OPEN_CHAR_CLASS:
+      elem->type = CHAR_CLASS;
+      break;
+    default:
+      break;
+    }
+  return REG_NOERROR;
+}
+
+  /* Helper function for parse_bracket_exp.
+     Build the equivalence class which is represented by NAME.
+     The result are written to MBCSET and SBCSET.
+     EQUIV_CLASS_ALLOC is the allocated size of mbcset->equiv_classes,
+     is a pointer argument since we may update it.  */
+
+static reg_errcode_t
+#ifdef RE_ENABLE_I18N
+build_equiv_class (bitset_t sbcset, re_charset_t *mbcset,
+		   Idx *equiv_class_alloc, const unsigned char *name)
+#else /* not RE_ENABLE_I18N */
+build_equiv_class (bitset_t sbcset, const unsigned char *name)
+#endif /* not RE_ENABLE_I18N */
+{
+#ifdef _LIBC
+  uint32_t nrules = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES);
+  if (nrules != 0)
+    {
+      const int32_t *table, *indirect;
+      const unsigned char *weights, *extra, *cp;
+      unsigned char char_buf[2];
+      int32_t idx1, idx2;
+      unsigned int ch;
+      size_t len;
+      /* Calculate the index for equivalence class.  */
+      cp = name;
+      table = (const int32_t *) _NL_CURRENT (LC_COLLATE, _NL_COLLATE_TABLEMB);
+      weights = (const unsigned char *) _NL_CURRENT (LC_COLLATE,
+					       _NL_COLLATE_WEIGHTMB);
+      extra = (const unsigned char *) _NL_CURRENT (LC_COLLATE,
+						   _NL_COLLATE_EXTRAMB);
+      indirect = (const int32_t *) _NL_CURRENT (LC_COLLATE,
+						_NL_COLLATE_INDIRECTMB);
+      idx1 = findidx (table, indirect, extra, &cp, -1);
+      if (BE (idx1 == 0 || *cp != '\0', 0))
+	/* This isn't a valid character.  */
+	return REG_ECOLLATE;
+
+      /* Build single byte matching table for this equivalence class.  */
+      len = weights[idx1 & 0xffffff];
+      for (ch = 0; ch < SBC_MAX; ++ch)
+	{
+	  char_buf[0] = ch;
+	  cp = char_buf;
+	  idx2 = findidx (table, indirect, extra, &cp, 1);
+/*
+	  idx2 = table[ch];
+*/
+	  if (idx2 == 0)
+	    /* This isn't a valid character.  */
+	    continue;
+	  /* Compare only if the length matches and the collation rule
+	     index is the same.  */
+	  if (len == weights[idx2 & 0xffffff] && (idx1 >> 24) == (idx2 >> 24))
+	    {
+	      int cnt = 0;
+
+	      while (cnt <= len &&
+		     weights[(idx1 & 0xffffff) + 1 + cnt]
+		     == weights[(idx2 & 0xffffff) + 1 + cnt])
+		++cnt;
+
+	      if (cnt > len)
+		bitset_set (sbcset, ch);
+	    }
+	}
+      /* Check whether the array has enough space.  */
+      if (BE (*equiv_class_alloc == mbcset->nequiv_classes, 0))
+	{
+	  /* Not enough, realloc it.  */
+	  /* +1 in case of mbcset->nequiv_classes is 0.  */
+	  Idx new_equiv_class_alloc = 2 * mbcset->nequiv_classes + 1;
+	  /* Use realloc since the array is NULL if *alloc == 0.  */
+	  int32_t *new_equiv_classes = re_realloc (mbcset->equiv_classes,
+						   int32_t,
+						   new_equiv_class_alloc);
+	  if (BE (new_equiv_classes == NULL, 0))
+	    return REG_ESPACE;
+	  mbcset->equiv_classes = new_equiv_classes;
+	  *equiv_class_alloc = new_equiv_class_alloc;
+	}
+      mbcset->equiv_classes[mbcset->nequiv_classes++] = idx1;
+    }
+  else
+#endif /* _LIBC */
+    {
+      if (BE (strlen ((const char *) name) != 1, 0))
+	return REG_ECOLLATE;
+      bitset_set (sbcset, *name);
+    }
+  return REG_NOERROR;
+}
+
+  /* Helper function for parse_bracket_exp.
+     Build the character class which is represented by NAME.
+     The result are written to MBCSET and SBCSET.
+     CHAR_CLASS_ALLOC is the allocated size of mbcset->char_classes,
+     is a pointer argument since we may update it.  */
+
+static reg_errcode_t
+#ifdef RE_ENABLE_I18N
+build_charclass (RE_TRANSLATE_TYPE trans, bitset_t sbcset,
+		 re_charset_t *mbcset, Idx *char_class_alloc,
+		 const char *class_name, reg_syntax_t syntax)
+#else /* not RE_ENABLE_I18N */
+build_charclass (RE_TRANSLATE_TYPE trans, bitset_t sbcset,
+		 const char *class_name, reg_syntax_t syntax)
+#endif /* not RE_ENABLE_I18N */
+{
+  int i;
+  const char *name = class_name;
+
+  /* In case of REG_ICASE "upper" and "lower" match the both of
+     upper and lower cases.  */
+  if ((syntax & RE_ICASE)
+      && (strcmp (name, "upper") == 0 || strcmp (name, "lower") == 0))
+    name = "alpha";
+
+#ifdef RE_ENABLE_I18N
+  /* Check the space of the arrays.  */
+  if (BE (*char_class_alloc == mbcset->nchar_classes, 0))
+    {
+      /* Not enough, realloc it.  */
+      /* +1 in case of mbcset->nchar_classes is 0.  */
+      Idx new_char_class_alloc = 2 * mbcset->nchar_classes + 1;
+      /* Use realloc since array is NULL if *alloc == 0.  */
+      wctype_t *new_char_classes = re_realloc (mbcset->char_classes, wctype_t,
+					       new_char_class_alloc);
+      if (BE (new_char_classes == NULL, 0))
+	return REG_ESPACE;
+      mbcset->char_classes = new_char_classes;
+      *char_class_alloc = new_char_class_alloc;
+    }
+  mbcset->char_classes[mbcset->nchar_classes++] = __wctype (name);
+#endif /* RE_ENABLE_I18N */
+
+#define BUILD_CHARCLASS_LOOP(ctype_func)	\
+  do {						\
+    if (BE (trans != NULL, 0))			\
+      {						\
+	for (i = 0; i < SBC_MAX; ++i)		\
+	  if (ctype_func (i))			\
+	    bitset_set (sbcset, trans[i]);	\
+      }						\
+    else					\
+      {						\
+	for (i = 0; i < SBC_MAX; ++i)		\
+	  if (ctype_func (i))			\
+	    bitset_set (sbcset, i);		\
+      }						\
+  } while (0)
+
+  if (strcmp (name, "alnum") == 0)
+    BUILD_CHARCLASS_LOOP (isalnum);
+  else if (strcmp (name, "cntrl") == 0)
+    BUILD_CHARCLASS_LOOP (iscntrl);
+  else if (strcmp (name, "lower") == 0)
+    BUILD_CHARCLASS_LOOP (islower);
+  else if (strcmp (name, "space") == 0)
+    BUILD_CHARCLASS_LOOP (isspace);
+  else if (strcmp (name, "alpha") == 0)
+    BUILD_CHARCLASS_LOOP (isalpha);
+  else if (strcmp (name, "digit") == 0)
+    BUILD_CHARCLASS_LOOP (isdigit);
+  else if (strcmp (name, "print") == 0)
+    BUILD_CHARCLASS_LOOP (isprint);
+  else if (strcmp (name, "upper") == 0)
+    BUILD_CHARCLASS_LOOP (isupper);
+  else if (strcmp (name, "blank") == 0)
+    BUILD_CHARCLASS_LOOP (isblank);
+  else if (strcmp (name, "graph") == 0)
+    BUILD_CHARCLASS_LOOP (isgraph);
+  else if (strcmp (name, "punct") == 0)
+    BUILD_CHARCLASS_LOOP (ispunct);
+  else if (strcmp (name, "xdigit") == 0)
+    BUILD_CHARCLASS_LOOP (isxdigit);
+  else
+    return REG_ECTYPE;
+
+  return REG_NOERROR;
+}
+
+static bin_tree_t *
+build_charclass_op (re_dfa_t *dfa, RE_TRANSLATE_TYPE trans,
+		    const char *class_name,
+		    const char *extra, bool non_match,
+		    reg_errcode_t *err)
+{
+  re_bitset_ptr_t sbcset;
+#ifdef RE_ENABLE_I18N
+  re_charset_t *mbcset;
+  Idx alloc = 0;
+#endif /* not RE_ENABLE_I18N */
+  reg_errcode_t ret;
+  re_token_t br_token;
+  bin_tree_t *tree;
+
+  sbcset = (re_bitset_ptr_t) calloc (sizeof (bitset_t), 1);
+  if (BE (sbcset == NULL, 0))
+    {
+      *err = REG_ESPACE;
+      return NULL;
+    }
+#ifdef RE_ENABLE_I18N
+  mbcset = (re_charset_t *) calloc (sizeof (re_charset_t), 1);
+  if (BE (mbcset == NULL, 0))
+    {
+      re_free (sbcset);
+      *err = REG_ESPACE;
+      return NULL;
+    }
+  mbcset->non_match = non_match;
+#endif /* RE_ENABLE_I18N */
+
+  /* We don't care the syntax in this case.  */
+  ret = build_charclass (trans, sbcset,
+#ifdef RE_ENABLE_I18N
+			 mbcset, &alloc,
+#endif /* RE_ENABLE_I18N */
+			 class_name, 0);
+
+  if (BE (ret != REG_NOERROR, 0))
+    {
+      re_free (sbcset);
+#ifdef RE_ENABLE_I18N
+      free_charset (mbcset);
+#endif /* RE_ENABLE_I18N */
+      *err = ret;
+      return NULL;
+    }
+  /* \w match '_' also.  */
+  for (; *extra; extra++)
+    bitset_set (sbcset, *extra);
+
+  /* If it is non-matching list.  */
+  if (non_match)
+    bitset_not (sbcset);
+
+#ifdef RE_ENABLE_I18N
+  /* Ensure only single byte characters are set.  */
+  if (dfa->mb_cur_max > 1)
+    bitset_mask (sbcset, dfa->sb_char);
+#endif
+
+  /* Build a tree for simple bracket.  */
+#if defined GCC_LINT || defined lint
+  memset (&br_token, 0, sizeof br_token);
+#endif
+  br_token.type = SIMPLE_BRACKET;
+  br_token.opr.sbcset = sbcset;
+  tree = create_token_tree (dfa, NULL, NULL, &br_token);
+  if (BE (tree == NULL, 0))
+    goto build_word_op_espace;
+
+#ifdef RE_ENABLE_I18N
+  if (dfa->mb_cur_max > 1)
+    {
+      bin_tree_t *mbc_tree;
+      /* Build a tree for complex bracket.  */
+      br_token.type = COMPLEX_BRACKET;
+      br_token.opr.mbcset = mbcset;
+      dfa->has_mb_node = 1;
+      mbc_tree = create_token_tree (dfa, NULL, NULL, &br_token);
+      if (BE (mbc_tree == NULL, 0))
+	goto build_word_op_espace;
+      /* Then join them by ALT node.  */
+      tree = create_tree (dfa, tree, mbc_tree, OP_ALT);
+      if (BE (mbc_tree != NULL, 1))
+	return tree;
+    }
+  else
+    {
+      free_charset (mbcset);
+      return tree;
+    }
+#else /* not RE_ENABLE_I18N */
+  return tree;
+#endif /* not RE_ENABLE_I18N */
+
+ build_word_op_espace:
+  re_free (sbcset);
+#ifdef RE_ENABLE_I18N
+  free_charset (mbcset);
+#endif /* RE_ENABLE_I18N */
+  *err = REG_ESPACE;
+  return NULL;
+}
+
+/* This is intended for the expressions like "a{1,3}".
+   Fetch a number from 'input', and return the number.
+   Return -1 if the number field is empty like "{,1}".
+   Return RE_DUP_MAX + 1 if the number field is too large.
+   Return -2 if an error occurred.  */
+
+static Idx
+fetch_number (re_string_t *input, re_token_t *token, reg_syntax_t syntax)
+{
+  Idx num = -1;
+  unsigned char c;
+  while (1)
+    {
+      fetch_token (token, input, syntax);
+      c = token->opr.c;
+      if (BE (token->type == END_OF_RE, 0))
+	return -2;
+      if (token->type == OP_CLOSE_DUP_NUM || c == ',')
+	break;
+      num = ((token->type != CHARACTER || c < '0' || '9' < c || num == -2)
+	     ? -2
+	     : num == -1
+	     ? c - '0'
+	     : MIN (RE_DUP_MAX + 1, num * 10 + c - '0'));
+    }
+  return num;
+}
+
+#ifdef RE_ENABLE_I18N
+static void
+free_charset (re_charset_t *cset)
+{
+  re_free (cset->mbchars);
+# ifdef _LIBC
+  re_free (cset->coll_syms);
+  re_free (cset->equiv_classes);
+  re_free (cset->range_starts);
+  re_free (cset->range_ends);
+# endif
+  re_free (cset->char_classes);
+  re_free (cset);
+}
+#endif /* RE_ENABLE_I18N */
+
+/* Functions for binary tree operation.  */
+
+/* Create a tree node.  */
+
+static bin_tree_t *
+create_tree (re_dfa_t *dfa, bin_tree_t *left, bin_tree_t *right,
+	     re_token_type_t type)
+{
+  re_token_t t;
+#if defined GCC_LINT || defined lint
+  memset (&t, 0, sizeof t);
+#endif
+  t.type = type;
+  return create_token_tree (dfa, left, right, &t);
+}
+
+static bin_tree_t *
+create_token_tree (re_dfa_t *dfa, bin_tree_t *left, bin_tree_t *right,
+		   const re_token_t *token)
+{
+  bin_tree_t *tree;
+  if (BE (dfa->str_tree_storage_idx == BIN_TREE_STORAGE_SIZE, 0))
+    {
+      bin_tree_storage_t *storage = re_malloc (bin_tree_storage_t, 1);
+
+      if (storage == NULL)
+	return NULL;
+      storage->next = dfa->str_tree_storage;
+      dfa->str_tree_storage = storage;
+      dfa->str_tree_storage_idx = 0;
+    }
+  tree = &dfa->str_tree_storage->data[dfa->str_tree_storage_idx++];
+
+  tree->parent = NULL;
+  tree->left = left;
+  tree->right = right;
+  tree->token = *token;
+  tree->token.duplicated = 0;
+  tree->token.opt_subexp = 0;
+  tree->first = NULL;
+  tree->next = NULL;
+  tree->node_idx = -1;
+
+  if (left != NULL)
+    left->parent = tree;
+  if (right != NULL)
+    right->parent = tree;
+  return tree;
+}
+
+/* Mark the tree SRC as an optional subexpression.
+   To be called from preorder or postorder.  */
+
+static reg_errcode_t
+mark_opt_subexp (void *extra, bin_tree_t *node)
+{
+  Idx idx = (uintptr_t) extra;
+  if (node->token.type == SUBEXP && node->token.opr.idx == idx)
+    node->token.opt_subexp = 1;
+
+  return REG_NOERROR;
+}
+
+/* Free the allocated memory inside NODE. */
+
+static void
+free_token (re_token_t *node)
+{
+#ifdef RE_ENABLE_I18N
+  if (node->type == COMPLEX_BRACKET && node->duplicated == 0)
+    free_charset (node->opr.mbcset);
+  else
+#endif /* RE_ENABLE_I18N */
+    if (node->type == SIMPLE_BRACKET && node->duplicated == 0)
+      re_free (node->opr.sbcset);
+}
+
+/* Worker function for tree walking.  Free the allocated memory inside NODE
+   and its children. */
+
+static reg_errcode_t
+free_tree (void *extra, bin_tree_t *node)
+{
+  free_token (&node->token);
+  return REG_NOERROR;
+}
+
+
+/* Duplicate the node SRC, and return new node.  This is a preorder
+   visit similar to the one implemented by the generic visitor, but
+   we need more infrastructure to maintain two parallel trees --- so,
+   it's easier to duplicate.  */
+
+static bin_tree_t *
+duplicate_tree (const bin_tree_t *root, re_dfa_t *dfa)
+{
+  const bin_tree_t *node;
+  bin_tree_t *dup_root;
+  bin_tree_t **p_new = &dup_root, *dup_node = root->parent;
+
+  for (node = root; ; )
+    {
+      /* Create a new tree and link it back to the current parent.  */
+      *p_new = create_token_tree (dfa, NULL, NULL, &node->token);
+      if (*p_new == NULL)
+	return NULL;
+      (*p_new)->parent = dup_node;
+      (*p_new)->token.duplicated = 1;
+      dup_node = *p_new;
+
+      /* Go to the left node, or up and to the right.  */
+      if (node->left)
+	{
+	  node = node->left;
+	  p_new = &dup_node->left;
+	}
+      else
+	{
+	  const bin_tree_t *prev = NULL;
+	  while (node->right == prev || node->right == NULL)
+	    {
+	      prev = node;
+	      node = node->parent;
+	      dup_node = dup_node->parent;
+	      if (!node)
+		return dup_root;
+	    }
+	  node = node->right;
+	  p_new = &dup_node->right;
+	}
+    }
+}
diff --git a/lib/regex.c b/lib/regex.c
new file mode 100644
index 0000000000..499e1f0e03
--- /dev/null
+++ b/lib/regex.c
@@ -0,0 +1,81 @@
+/* Extended regular expression matching and search library.
+   Copyright (C) 2002-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Isamu Hasegawa <[email-masked]>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _LIBC
+# include <config.h>
+
+# if (__GNUC__ == 4 && 6 <= __GNUC_MINOR__) || 4 < __GNUC__
+#  pragma GCC diagnostic ignored "-Wsuggest-attribute=pure"
+# endif
+# if (__GNUC__ == 4 && 3 <= __GNUC_MINOR__) || 4 < __GNUC__
+#  pragma GCC diagnostic ignored "-Wold-style-definition"
+#  pragma GCC diagnostic ignored "-Wtype-limits"
+# endif
+#endif
+
+/* Make sure no one compiles this code with a C++ compiler.  */
+#if defined __cplusplus && defined _LIBC
+# error "This is C code, use a C compiler"
+#endif
+
+#ifdef _LIBC
+/* We have to keep the namespace clean.  */
+# define regfree(preg) __regfree (preg)
+# define regexec(pr, st, nm, pm, ef) __regexec (pr, st, nm, pm, ef)
+# define regcomp(preg, pattern, cflags) __regcomp (preg, pattern, cflags)
+# define regerror(errcode, preg, errbuf, errbuf_size) \
+	__regerror(errcode, preg, errbuf, errbuf_size)
+# define re_set_registers(bu, re, nu, st, en) \
+	__re_set_registers (bu, re, nu, st, en)
+# define re_match_2(bufp, string1, size1, string2, size2, pos, regs, stop) \
+	__re_match_2 (bufp, string1, size1, string2, size2, pos, regs, stop)
+# define re_match(bufp, string, size, pos, regs) \
+	__re_match (bufp, string, size, pos, regs)
+# define re_search(bufp, string, size, startpos, range, regs) \
+	__re_search (bufp, string, size, startpos, range, regs)
+# define re_compile_pattern(pattern, length, bufp) \
+	__re_compile_pattern (pattern, length, bufp)
+# define re_set_syntax(syntax) __re_set_syntax (syntax)
+# define re_search_2(bufp, st1, s1, st2, s2, startpos, range, regs, stop) \
+	__re_search_2 (bufp, st1, s1, st2, s2, startpos, range, regs, stop)
+# define re_compile_fastmap(bufp) __re_compile_fastmap (bufp)
+
+# include "../locale/localeinfo.h"
+#endif
+
+/* On some systems, limits.h sets RE_DUP_MAX to a lower value than
+   GNU regex allows.  Include it before <regex.h>, which correctly
+   #undefs RE_DUP_MAX and sets it to the right value.  */
+#include <limits.h>
+
+#include <regex.h>
+#include "regex_internal.h"
+
+#include "regex_internal.c"
+#include "regcomp.c"
+#include "regexec.c"
+
+/* Binary backward compatibility.  */
+#if _LIBC
+# include <shlib-compat.h>
+# if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_3)
+link_warning (re_max_failures, "the 're_max_failures' variable is obsolete and will go away.")
+int re_max_failures = 2000;
+# endif
+#endif
diff --git a/lib/regex.h b/lib/regex.h
new file mode 100644
index 0000000000..f2ac9507ad
--- /dev/null
+++ b/lib/regex.h
@@ -0,0 +1,658 @@
+/* Definitions for data structures and routines for the regular
+   expression library.
+   Copyright (C) 1985, 1989-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _REGEX_H
+#define _REGEX_H 1
+
+#include <sys/types.h>
+
+/* Allow the use in C++ code.  */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Define __USE_GNU to declare GNU extensions that violate the
+   POSIX name space rules.  */
+#ifdef _GNU_SOURCE
+# define __USE_GNU 1
+#endif
+
+#ifdef _REGEX_LARGE_OFFSETS
+
+/* Use types and values that are wide enough to represent signed and
+   unsigned byte offsets in memory.  This currently works only when
+   the regex code is used outside of the GNU C library; it is not yet
+   supported within glibc itself, and glibc users should not define
+   _REGEX_LARGE_OFFSETS.  */
+
+/* The type of object sizes.  */
+typedef size_t __re_size_t;
+
+/* The type of object sizes, in places where the traditional code
+   uses unsigned long int.  */
+typedef size_t __re_long_size_t;
+
+#else
+
+/* The traditional GNU regex implementation mishandles strings longer
+   than INT_MAX.  */
+typedef unsigned int __re_size_t;
+typedef unsigned long int __re_long_size_t;
+
+#endif
+
+/* The following two types have to be signed and unsigned integer type
+   wide enough to hold a value of a pointer.  For most ANSI compilers
+   ptrdiff_t and size_t should be likely OK.  Still size of these two
+   types is 2 for Microsoft C.  Ugh... */
+typedef long int s_reg_t;
+typedef unsigned long int active_reg_t;
+
+/* The following bits are used to determine the regexp syntax we
+   recognize.  The set/not-set meanings are chosen so that Emacs syntax
+   remains the value 0.  The bits are given in alphabetical order, and
+   the definitions shifted by one from the previous bit; thus, when we
+   add or remove a bit, only one other definition need change.  */
+typedef unsigned long int reg_syntax_t;
+
+#ifdef __USE_GNU
+/* If this bit is not set, then \ inside a bracket expression is literal.
+   If set, then such a \ quotes the following character.  */
+# define RE_BACKSLASH_ESCAPE_IN_LISTS ((unsigned long int) 1)
+
+/* If this bit is not set, then + and ? are operators, and \+ and \? are
+     literals.
+   If set, then \+ and \? are operators and + and ? are literals.  */
+# define RE_BK_PLUS_QM (RE_BACKSLASH_ESCAPE_IN_LISTS << 1)
+
+/* If this bit is set, then character classes are supported.  They are:
+     [:alpha:], [:upper:], [:lower:],  [:digit:], [:alnum:], [:xdigit:],
+     [:space:], [:print:], [:punct:], [:graph:], and [:cntrl:].
+   If not set, then character classes are not supported.  */
+# define RE_CHAR_CLASSES (RE_BK_PLUS_QM << 1)
+
+/* If this bit is set, then ^ and $ are always anchors (outside bracket
+     expressions, of course).
+   If this bit is not set, then it depends:
+	^  is an anchor if it is at the beginning of a regular
+	   expression or after an open-group or an alternation operator;
+	$  is an anchor if it is at the end of a regular expression, or
+	   before a close-group or an alternation operator.
+
+   This bit could be (re)combined with RE_CONTEXT_INDEP_OPS, because
+   POSIX draft 11.2 says that * etc. in leading positions is undefined.
+   We already implemented a previous draft which made those constructs
+   invalid, though, so we haven't changed the code back.  */
+# define RE_CONTEXT_INDEP_ANCHORS (RE_CHAR_CLASSES << 1)
+
+/* If this bit is set, then special characters are always special
+     regardless of where they are in the pattern.
+   If this bit is not set, then special characters are special only in
+     some contexts; otherwise they are ordinary.  Specifically,
+     * + ? and intervals are only special when not after the beginning,
+     open-group, or alternation operator.  */
+# define RE_CONTEXT_INDEP_OPS (RE_CONTEXT_INDEP_ANCHORS << 1)
+
+/* If this bit is set, then *, +, ?, and { cannot be first in an re or
+     immediately after an alternation or begin-group operator.  */
+# define RE_CONTEXT_INVALID_OPS (RE_CONTEXT_INDEP_OPS << 1)
+
+/* If this bit is set, then . matches newline.
+   If not set, then it doesn't.  */
+# define RE_DOT_NEWLINE (RE_CONTEXT_INVALID_OPS << 1)
+
+/* If this bit is set, then . doesn't match NUL.
+   If not set, then it does.  */
+# define RE_DOT_NOT_NULL (RE_DOT_NEWLINE << 1)
+
+/* If this bit is set, nonmatching lists [^...] do not match newline.
+   If not set, they do.  */
+# define RE_HAT_LISTS_NOT_NEWLINE (RE_DOT_NOT_NULL << 1)
+
+/* If this bit is set, either \{...\} or {...} defines an
+     interval, depending on RE_NO_BK_BRACES.
+   If not set, \{, \}, {, and } are literals.  */
+# define RE_INTERVALS (RE_HAT_LISTS_NOT_NEWLINE << 1)
+
+/* If this bit is set, +, ? and | aren't recognized as operators.
+   If not set, they are.  */
+# define RE_LIMITED_OPS (RE_INTERVALS << 1)
+
+/* If this bit is set, newline is an alternation operator.
+   If not set, newline is literal.  */
+# define RE_NEWLINE_ALT (RE_LIMITED_OPS << 1)
+
+/* If this bit is set, then '{...}' defines an interval, and \{ and \}
+     are literals.
+  If not set, then '\{...\}' defines an interval.  */
+# define RE_NO_BK_BRACES (RE_NEWLINE_ALT << 1)
+
+/* If this bit is set, (...) defines a group, and \( and \) are literals.
+   If not set, \(...\) defines a group, and ( and ) are literals.  */
+# define RE_NO_BK_PARENS (RE_NO_BK_BRACES << 1)
+
+/* If this bit is set, then \<digit> matches <digit>.
+   If not set, then \<digit> is a back-reference.  */
+# define RE_NO_BK_REFS (RE_NO_BK_PARENS << 1)
+
+/* If this bit is set, then | is an alternation operator, and \| is literal.
+   If not set, then \| is an alternation operator, and | is literal.  */
+# define RE_NO_BK_VBAR (RE_NO_BK_REFS << 1)
+
+/* If this bit is set, then an ending range point collating higher
+     than the starting range point, as in [z-a], is invalid.
+   If not set, then when ending range point collates higher than the
+     starting range point, the range is ignored.  */
+# define RE_NO_EMPTY_RANGES (RE_NO_BK_VBAR << 1)
+
+/* If this bit is set, then an unmatched ) is ordinary.
+   If not set, then an unmatched ) is invalid.  */
+# define RE_UNMATCHED_RIGHT_PAREN_ORD (RE_NO_EMPTY_RANGES << 1)
+
+/* If this bit is set, succeed as soon as we match the whole pattern,
+   without further backtracking.  */
+# define RE_NO_POSIX_BACKTRACKING (RE_UNMATCHED_RIGHT_PAREN_ORD << 1)
+
+/* If this bit is set, do not process the GNU regex operators.
+   If not set, then the GNU regex operators are recognized. */
+# define RE_NO_GNU_OPS (RE_NO_POSIX_BACKTRACKING << 1)
+
+/* If this bit is set, turn on internal regex debugging.
+   If not set, and debugging was on, turn it off.
+   This only works if regex.c is compiled -DDEBUG.
+   We define this bit always, so that all that's needed to turn on
+   debugging is to recompile regex.c; the calling code can always have
+   this bit set, and it won't affect anything in the normal case. */
+# define RE_DEBUG (RE_NO_GNU_OPS << 1)
+
+/* If this bit is set, a syntactically invalid interval is treated as
+   a string of ordinary characters.  For example, the ERE 'a{1' is
+   treated as 'a\{1'.  */
+# define RE_INVALID_INTERVAL_ORD (RE_DEBUG << 1)
+
+/* If this bit is set, then ignore case when matching.
+   If not set, then case is significant.  */
+# define RE_ICASE (RE_INVALID_INTERVAL_ORD << 1)
+
+/* This bit is used internally like RE_CONTEXT_INDEP_ANCHORS but only
+   for ^, because it is difficult to scan the regex backwards to find
+   whether ^ should be special.  */
+# define RE_CARET_ANCHORS_HERE (RE_ICASE << 1)
+
+/* If this bit is set, then \{ cannot be first in a regex or
+   immediately after an alternation, open-group or \} operator.  */
+# define RE_CONTEXT_INVALID_DUP (RE_CARET_ANCHORS_HERE << 1)
+
+/* If this bit is set, then no_sub will be set to 1 during
+   re_compile_pattern.  */
+# define RE_NO_SUB (RE_CONTEXT_INVALID_DUP << 1)
+#endif
+
+/* This global variable defines the particular regexp syntax to use (for
+   some interfaces).  When a regexp is compiled, the syntax used is
+   stored in the pattern buffer, so changing this does not affect
+   already-compiled regexps.  */
+extern reg_syntax_t re_syntax_options;
+
+#ifdef __USE_GNU
+/* Define combinations of the above bits for the standard possibilities.
+   (The [[[ comments delimit what gets put into the Texinfo file, so
+   don't delete them!)  */
+/* [[[begin syntaxes]]] */
+# define RE_SYNTAX_EMACS 0
+
+# define RE_SYNTAX_AWK							\
+  (RE_BACKSLASH_ESCAPE_IN_LISTS   | RE_DOT_NOT_NULL			\
+   | RE_NO_BK_PARENS              | RE_NO_BK_REFS			\
+   | RE_NO_BK_VBAR                | RE_NO_EMPTY_RANGES			\
+   | RE_DOT_NEWLINE		  | RE_CONTEXT_INDEP_ANCHORS		\
+   | RE_CHAR_CLASSES							\
+   | RE_UNMATCHED_RIGHT_PAREN_ORD | RE_NO_GNU_OPS)
+
+# define RE_SYNTAX_GNU_AWK						\
+  ((RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS		\
+    | RE_INVALID_INTERVAL_ORD)						\
+   & ~(RE_DOT_NOT_NULL | RE_CONTEXT_INDEP_OPS				\
+      | RE_CONTEXT_INVALID_OPS ))
+
+# define RE_SYNTAX_POSIX_AWK						\
+  (RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS		\
+   | RE_INTERVALS	    | RE_NO_GNU_OPS				\
+   | RE_INVALID_INTERVAL_ORD)
+
+# define RE_SYNTAX_GREP							\
+  ((RE_SYNTAX_POSIX_BASIC | RE_NEWLINE_ALT)				\
+   & ~(RE_CONTEXT_INVALID_DUP | RE_DOT_NOT_NULL))
+
+# define RE_SYNTAX_EGREP						\
+  ((RE_SYNTAX_POSIX_EXTENDED | RE_INVALID_INTERVAL_ORD | RE_NEWLINE_ALT) \
+   & ~(RE_CONTEXT_INVALID_OPS | RE_DOT_NOT_NULL))
+
+/* POSIX grep -E behavior is no longer incompatible with GNU.  */
+# define RE_SYNTAX_POSIX_EGREP						\
+  RE_SYNTAX_EGREP
+
+/* P1003.2/D11.2, section 4.20.7.1, lines 5078ff.  */
+# define RE_SYNTAX_ED RE_SYNTAX_POSIX_BASIC
+
+# define RE_SYNTAX_SED RE_SYNTAX_POSIX_BASIC
+
+/* Syntax bits common to both basic and extended POSIX regex syntax.  */
+# define _RE_SYNTAX_POSIX_COMMON					\
+  (RE_CHAR_CLASSES | RE_DOT_NEWLINE      | RE_DOT_NOT_NULL		\
+   | RE_INTERVALS  | RE_NO_EMPTY_RANGES)
+
+# define RE_SYNTAX_POSIX_BASIC						\
+  (_RE_SYNTAX_POSIX_COMMON | RE_BK_PLUS_QM | RE_CONTEXT_INVALID_DUP)
+
+/* Differs from ..._POSIX_BASIC only in that RE_BK_PLUS_QM becomes
+   RE_LIMITED_OPS, i.e., \? \+ \| are not recognized.  Actually, this
+   isn't minimal, since other operators, such as \`, aren't disabled.  */
+# define RE_SYNTAX_POSIX_MINIMAL_BASIC					\
+  (_RE_SYNTAX_POSIX_COMMON | RE_LIMITED_OPS)
+
+# define RE_SYNTAX_POSIX_EXTENDED					\
+  (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS			\
+   | RE_CONTEXT_INDEP_OPS   | RE_NO_BK_BRACES				\
+   | RE_NO_BK_PARENS        | RE_NO_BK_VBAR				\
+   | RE_CONTEXT_INVALID_OPS | RE_UNMATCHED_RIGHT_PAREN_ORD)
+
+/* Differs from ..._POSIX_EXTENDED in that RE_CONTEXT_INDEP_OPS is
+   removed and RE_NO_BK_REFS is added.  */
+# define RE_SYNTAX_POSIX_MINIMAL_EXTENDED				\
+  (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS			\
+   | RE_CONTEXT_INVALID_OPS | RE_NO_BK_BRACES				\
+   | RE_NO_BK_PARENS        | RE_NO_BK_REFS				\
+   | RE_NO_BK_VBAR	    | RE_UNMATCHED_RIGHT_PAREN_ORD)
+/* [[[end syntaxes]]] */
+
+/* Maximum number of duplicates an interval can allow.  POSIX-conforming
+   systems might define this in <limits.h>, but we want our
+   value, so remove any previous define.  */
+# ifdef _REGEX_INCLUDE_LIMITS_H
+#  include <limits.h>
+# endif
+# ifdef RE_DUP_MAX
+#  undef RE_DUP_MAX
+# endif
+
+/* RE_DUP_MAX is 2**15 - 1 because an earlier implementation stored
+   the counter as a 2-byte signed integer.  This is no longer true, so
+   RE_DUP_MAX could be increased to (INT_MAX / 10 - 1), or to
+   ((SIZE_MAX - 9) / 10) if _REGEX_LARGE_OFFSETS is defined.
+   However, there would be a huge performance problem if someone
+   actually used a pattern like a\{214748363\}, so RE_DUP_MAX retains
+   its historical value.  */
+# define RE_DUP_MAX (0x7fff)
+#endif
+
+
+/* POSIX 'cflags' bits (i.e., information for 'regcomp').  */
+
+/* If this bit is set, then use extended regular expression syntax.
+   If not set, then use basic regular expression syntax.  */
+#define REG_EXTENDED 1
+
+/* If this bit is set, then ignore case when matching.
+   If not set, then case is significant.  */
+#define REG_ICASE (1 << 1)
+
+/* If this bit is set, then anchors do not match at newline
+     characters in the string.
+   If not set, then anchors do match at newlines.  */
+#define REG_NEWLINE (1 << 2)
+
+/* If this bit is set, then report only success or fail in regexec.
+   If not set, then returns differ between not matching and errors.  */
+#define REG_NOSUB (1 << 3)
+
+
+/* POSIX 'eflags' bits (i.e., information for regexec).  */
+
+/* If this bit is set, then the beginning-of-line operator doesn't match
+     the beginning of the string (presumably because it's not the
+     beginning of a line).
+   If not set, then the beginning-of-line operator does match the
+     beginning of the string.  */
+#define REG_NOTBOL 1
+
+/* Like REG_NOTBOL, except for the end-of-line.  */
+#define REG_NOTEOL (1 << 1)
+
+/* Use PMATCH[0] to delimit the start and end of the search in the
+   buffer.  */
+#define REG_STARTEND (1 << 2)
+
+
+/* If any error codes are removed, changed, or added, update the
+   '__re_error_msgid' table in regcomp.c.  */
+
+typedef enum
+{
+  _REG_ENOSYS = -1,	/* This will never happen for this implementation.  */
+  _REG_NOERROR = 0,	/* Success.  */
+  _REG_NOMATCH,		/* Didn't find a match (for regexec).  */
+
+  /* POSIX regcomp return error codes.  (In the order listed in the
+     standard.)  */
+  _REG_BADPAT,		/* Invalid pattern.  */
+  _REG_ECOLLATE,	/* Invalid collating element.  */
+  _REG_ECTYPE,		/* Invalid character class name.  */
+  _REG_EESCAPE,		/* Trailing backslash.  */
+  _REG_ESUBREG,		/* Invalid back reference.  */
+  _REG_EBRACK,		/* Unmatched left bracket.  */
+  _REG_EPAREN,		/* Parenthesis imbalance.  */
+  _REG_EBRACE,		/* Unmatched \{.  */
+  _REG_BADBR,		/* Invalid contents of \{\}.  */
+  _REG_ERANGE,		/* Invalid range end.  */
+  _REG_ESPACE,		/* Ran out of memory.  */
+  _REG_BADRPT,		/* No preceding re for repetition op.  */
+
+  /* Error codes we've added.  */
+  _REG_EEND,		/* Premature end.  */
+  _REG_ESIZE,		/* Too large (e.g., repeat count too large).  */
+  _REG_ERPAREN		/* Unmatched ) or \); not returned from regcomp.  */
+} reg_errcode_t;
+
+#if defined _XOPEN_SOURCE || defined __USE_XOPEN2K
+# define REG_ENOSYS	_REG_ENOSYS
+#endif
+#define REG_NOERROR	_REG_NOERROR
+#define REG_NOMATCH	_REG_NOMATCH
+#define REG_BADPAT	_REG_BADPAT
+#define REG_ECOLLATE	_REG_ECOLLATE
+#define REG_ECTYPE	_REG_ECTYPE
+#define REG_EESCAPE	_REG_EESCAPE
+#define REG_ESUBREG	_REG_ESUBREG
+#define REG_EBRACK	_REG_EBRACK
+#define REG_EPAREN	_REG_EPAREN
+#define REG_EBRACE	_REG_EBRACE
+#define REG_BADBR	_REG_BADBR
+#define REG_ERANGE	_REG_ERANGE
+#define REG_ESPACE	_REG_ESPACE
+#define REG_BADRPT	_REG_BADRPT
+#define REG_EEND	_REG_EEND
+#define REG_ESIZE	_REG_ESIZE
+#define REG_ERPAREN	_REG_ERPAREN
+
+/* This data structure represents a compiled pattern.  Before calling
+   the pattern compiler, the fields 'buffer', 'allocated', 'fastmap',
+   and 'translate' can be set.  After the pattern has been compiled,
+   the fields 're_nsub', 'not_bol' and 'not_eol' are available.  All
+   other fields are private to the regex routines.  */
+
+#ifndef RE_TRANSLATE_TYPE
+# define __RE_TRANSLATE_TYPE unsigned char *
+# ifdef __USE_GNU
+#  define RE_TRANSLATE_TYPE __RE_TRANSLATE_TYPE
+# endif
+#endif
+
+#ifdef __USE_GNU
+# define __REPB_PREFIX(name) name
+#else
+# define __REPB_PREFIX(name) __##name
+#endif
+
+struct re_pattern_buffer
+{
+  /* Space that holds the compiled pattern.  The type
+     'struct re_dfa_t' is private and is not declared here.  */
+  struct re_dfa_t *__REPB_PREFIX(buffer);
+
+  /* Number of bytes to which 'buffer' points.  */
+  __re_long_size_t __REPB_PREFIX(allocated);
+
+  /* Number of bytes actually used in 'buffer'.  */
+  __re_long_size_t __REPB_PREFIX(used);
+
+  /* Syntax setting with which the pattern was compiled.  */
+  reg_syntax_t __REPB_PREFIX(syntax);
+
+  /* Pointer to a fastmap, if any, otherwise zero.  re_search uses the
+     fastmap, if there is one, to skip over impossible starting points
+     for matches.  */
+  char *__REPB_PREFIX(fastmap);
+
+  /* Either a translate table to apply to all characters before
+     comparing them, or zero for no translation.  The translation is
+     applied to a pattern when it is compiled and to a string when it
+     is matched.  */
+  __RE_TRANSLATE_TYPE __REPB_PREFIX(translate);
+
+  /* Number of subexpressions found by the compiler.  */
+  size_t re_nsub;
+
+  /* Zero if this pattern cannot match the empty string, one else.
+     Well, in truth it's used only in 're_search_2', to see whether or
+     not we should use the fastmap, so we don't set this absolutely
+     perfectly; see 're_compile_fastmap' (the "duplicate" case).  */
+  unsigned __REPB_PREFIX(can_be_null) : 1;
+
+  /* If REGS_UNALLOCATED, allocate space in the 'regs' structure
+     for 'max (RE_NREGS, re_nsub + 1)' groups.
+     If REGS_REALLOCATE, reallocate space if necessary.
+     If REGS_FIXED, use what's there.  */
+#ifdef __USE_GNU
+# define REGS_UNALLOCATED 0
+# define REGS_REALLOCATE 1
+# define REGS_FIXED 2
+#endif
+  unsigned __REPB_PREFIX(regs_allocated) : 2;
+
+  /* Set to zero when 're_compile_pattern' compiles a pattern; set to
+     one by 're_compile_fastmap' if it updates the fastmap.  */
+  unsigned __REPB_PREFIX(fastmap_accurate) : 1;
+
+  /* If set, 're_match_2' does not return information about
+     subexpressions.  */
+  unsigned __REPB_PREFIX(no_sub) : 1;
+
+  /* If set, a beginning-of-line anchor doesn't match at the beginning
+     of the string.  */
+  unsigned __REPB_PREFIX(not_bol) : 1;
+
+  /* Similarly for an end-of-line anchor.  */
+  unsigned __REPB_PREFIX(not_eol) : 1;
+
+  /* If true, an anchor at a newline matches.  */
+  unsigned __REPB_PREFIX(newline_anchor) : 1;
+};
+
+typedef struct re_pattern_buffer regex_t;
+
+/* Type for byte offsets within the string.  POSIX mandates this.  */
+#ifdef _REGEX_LARGE_OFFSETS
+/* POSIX 1003.1-2008 requires that regoff_t be at least as wide as
+   ptrdiff_t and ssize_t.  We don't know of any hosts where ptrdiff_t
+   is wider than ssize_t, so ssize_t is safe.  ptrdiff_t is not
+   visible here, so use ssize_t.  */
+typedef ssize_t regoff_t;
+#else
+/* The traditional GNU regex implementation mishandles strings longer
+   than INT_MAX.  */
+typedef int regoff_t;
+#endif
+
+
+#ifdef __USE_GNU
+/* This is the structure we store register match data in.  See
+   regex.texinfo for a full description of what registers match.  */
+struct re_registers
+{
+  __re_size_t num_regs;
+  regoff_t *start;
+  regoff_t *end;
+};
+
+
+/* If 'regs_allocated' is REGS_UNALLOCATED in the pattern buffer,
+   're_match_2' returns information about at least this many registers
+   the first time a 'regs' structure is passed.  */
+# ifndef RE_NREGS
+#  define RE_NREGS 30
+# endif
+#endif
+
+
+/* POSIX specification for registers.  Aside from the different names than
+   're_registers', POSIX uses an array of structures, instead of a
+   structure of arrays.  */
+typedef struct
+{
+  regoff_t rm_so;  /* Byte offset from string's start to substring's start.  */
+  regoff_t rm_eo;  /* Byte offset from string's start to substring's end.  */
+} regmatch_t;
+
+/* Declarations for routines.  */
+
+#ifdef __USE_GNU
+/* Sets the current default syntax to SYNTAX, and return the old syntax.
+   You can also simply assign to the 're_syntax_options' variable.  */
+extern reg_syntax_t re_set_syntax (reg_syntax_t __syntax);
+
+/* Compile the regular expression PATTERN, with length LENGTH
+   and syntax given by the global 're_syntax_options', into the buffer
+   BUFFER.  Return NULL if successful, and an error string if not.
+
+   To free the allocated storage, you must call 'regfree' on BUFFER.
+   Note that the translate table must either have been initialized by
+   'regcomp', with a malloc'ed value, or set to NULL before calling
+   'regfree'.  */
+extern const char *re_compile_pattern (const char *__pattern, size_t __length,
+				       struct re_pattern_buffer *__buffer);
+
+
+/* Compile a fastmap for the compiled pattern in BUFFER; used to
+   accelerate searches.  Return 0 if successful and -2 if was an
+   internal error.  */
+extern int re_compile_fastmap (struct re_pattern_buffer *__buffer);
+
+
+/* Search in the string STRING (with length LENGTH) for the pattern
+   compiled into BUFFER.  Start searching at position START, for RANGE
+   characters.  Return the starting position of the match, -1 for no
+   match, or -2 for an internal error.  Also return register
+   information in REGS (if REGS and BUFFER->no_sub are nonzero).  */
+extern regoff_t re_search (struct re_pattern_buffer *__buffer,
+			   const char *__String, regoff_t __length,
+			   regoff_t __start, regoff_t __range,
+			   struct re_registers *__regs);
+
+
+/* Like 're_search', but search in the concatenation of STRING1 and
+   STRING2.  Also, stop searching at index START + STOP.  */
+extern regoff_t re_search_2 (struct re_pattern_buffer *__buffer,
+			     const char *__string1, regoff_t __length1,
+			     const char *__string2, regoff_t __length2,
+			     regoff_t __start, regoff_t __range,
+			     struct re_registers *__regs,
+			     regoff_t __stop);
+
+
+/* Like 're_search', but return how many characters in STRING the regexp
+   in BUFFER matched, starting at position START.  */
+extern regoff_t re_match (struct re_pattern_buffer *__buffer,
+			  const char *__String, regoff_t __length,
+			  regoff_t __start, struct re_registers *__regs);
+
+
+/* Relates to 're_match' as 're_search_2' relates to 're_search'.  */
+extern regoff_t re_match_2 (struct re_pattern_buffer *__buffer,
+			    const char *__string1, regoff_t __length1,
+			    const char *__string2, regoff_t __length2,
+			    regoff_t __start, struct re_registers *__regs,
+			    regoff_t __stop);
+
+
+/* Set REGS to hold NUM_REGS registers, storing them in STARTS and
+   ENDS.  Subsequent matches using BUFFER and REGS will use this memory
+   for recording register information.  STARTS and ENDS must be
+   allocated with malloc, and must each be at least 'NUM_REGS * sizeof
+   (regoff_t)' bytes long.
+
+   If NUM_REGS == 0, then subsequent matches should allocate their own
+   register data.
+
+   Unless this function is called, the first search or match using
+   BUFFER will allocate its own register data, without
+   freeing the old data.  */
+extern void re_set_registers (struct re_pattern_buffer *__buffer,
+			      struct re_registers *__regs,
+			      __re_size_t __num_regs,
+			      regoff_t *__starts, regoff_t *__ends);
+#endif	/* Use GNU */
+
+#if defined _REGEX_RE_COMP || (defined _LIBC && defined __USE_MISC)
+# ifndef _CRAY
+/* 4.2 bsd compatibility.  */
+extern char *re_comp (const char *);
+extern int re_exec (const char *);
+# endif
+#endif
+
+/* For plain 'restrict', use glibc's __restrict if defined.
+   Otherwise, GCC 2.95 and later have "__restrict"; C99 compilers have
+   "restrict", and "configure" may have defined "restrict".
+   Other compilers use __restrict, __restrict__, and _Restrict, and
+   'configure' might #define 'restrict' to those words, so pick a
+   different name.  */
+#ifndef _Restrict_
+# if defined __restrict || 2 < __GNUC__ + (95 <= __GNUC_MINOR__)
+#  define _Restrict_ __restrict
+# elif 199901L <= __STDC_VERSION__ || defined restrict
+#  define _Restrict_ restrict
+# else
+#  define _Restrict_
+# endif
+#endif
+/* For [restrict], use glibc's __restrict_arr if available.
+   Otherwise, GCC 3.1 (not in C++ mode) and C99 support [restrict].  */
+#ifndef _Restrict_arr_
+# ifdef __restrict_arr
+#  define _Restrict_arr_ __restrict_arr
+# elif ((199901L <= __STDC_VERSION__ || 3 < __GNUC__ + (1 <= __GNUC_MINOR__)) \
+        && !defined __GNUG__)
+#  define _Restrict_arr_ _Restrict_
+# else
+#  define _Restrict_arr_
+# endif
+#endif
+
+/* POSIX compatibility.  */
+extern int regcomp (regex_t *_Restrict_ __preg,
+		    const char *_Restrict_ __pattern,
+		    int __cflags);
+
+extern int regexec (const regex_t *_Restrict_ __preg,
+		    const char *_Restrict_ __String, size_t __nmatch,
+		    regmatch_t __pmatch[_Restrict_arr_],
+		    int __eflags);
+
+extern size_t regerror (int __errcode, const regex_t *_Restrict_ __preg,
+			char *_Restrict_ __errbuf, size_t __errbuf_size);
+
+extern void regfree (regex_t *__preg);
+
+
+#ifdef __cplusplus
+}
+#endif	/* C++ */
+
+#endif /* regex.h */
diff --git a/lib/regex_internal.c b/lib/regex_internal.c
new file mode 100644
index 0000000000..32373565e6
--- /dev/null
+++ b/lib/regex_internal.c
@@ -0,0 +1,1740 @@
+/* Extended regular expression matching and search library.
+   Copyright (C) 2002-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Isamu Hasegawa <[email-masked]>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+static void re_string_construct_common (const char *str, Idx len,
+					re_string_t *pstr,
+					RE_TRANSLATE_TYPE trans, bool icase,
+					const re_dfa_t *dfa);
+static re_dfastate_t *create_ci_newstate (const re_dfa_t *dfa,
+					  const re_node_set *nodes,
+					  re_hashval_t hash);
+static re_dfastate_t *create_cd_newstate (const re_dfa_t *dfa,
+					  const re_node_set *nodes,
+					  unsigned int context,
+					  re_hashval_t hash);
+static reg_errcode_t re_string_realloc_buffers (re_string_t *pstr,
+						Idx new_buf_len);
+#ifdef RE_ENABLE_I18N
+static void build_wcs_buffer (re_string_t *pstr);
+static reg_errcode_t build_wcs_upper_buffer (re_string_t *pstr);
+#endif /* RE_ENABLE_I18N */
+static void build_upper_buffer (re_string_t *pstr);
+static void re_string_translate_buffer (re_string_t *pstr);
+static unsigned int re_string_context_at (const re_string_t *input, Idx idx,
+					  int eflags) __attribute__ ((pure));
+
+/* Functions for string operation.  */
+
+/* This function allocate the buffers.  It is necessary to call
+   re_string_reconstruct before using the object.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+re_string_allocate (re_string_t *pstr, const char *str, Idx len, Idx init_len,
+		    RE_TRANSLATE_TYPE trans, bool icase, const re_dfa_t *dfa)
+{
+  reg_errcode_t ret;
+  Idx init_buf_len;
+
+  /* Ensure at least one character fits into the buffers.  */
+  if (init_len < dfa->mb_cur_max)
+    init_len = dfa->mb_cur_max;
+  init_buf_len = (len + 1 < init_len) ? len + 1: init_len;
+  re_string_construct_common (str, len, pstr, trans, icase, dfa);
+
+  ret = re_string_realloc_buffers (pstr, init_buf_len);
+  if (BE (ret != REG_NOERROR, 0))
+    return ret;
+
+  pstr->word_char = dfa->word_char;
+  pstr->word_ops_used = dfa->word_ops_used;
+  pstr->mbs = pstr->mbs_allocated ? pstr->mbs : (unsigned char *) str;
+  pstr->valid_len = (pstr->mbs_allocated || dfa->mb_cur_max > 1) ? 0 : len;
+  pstr->valid_raw_len = pstr->valid_len;
+  return REG_NOERROR;
+}
+
+/* This function allocate the buffers, and initialize them.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+re_string_construct (re_string_t *pstr, const char *str, Idx len,
+		     RE_TRANSLATE_TYPE trans, bool icase, const re_dfa_t *dfa)
+{
+  reg_errcode_t ret;
+  memset (pstr, '\0', sizeof (re_string_t));
+  re_string_construct_common (str, len, pstr, trans, icase, dfa);
+
+  if (len > 0)
+    {
+      ret = re_string_realloc_buffers (pstr, len + 1);
+      if (BE (ret != REG_NOERROR, 0))
+	return ret;
+    }
+  pstr->mbs = pstr->mbs_allocated ? pstr->mbs : (unsigned char *) str;
+
+  if (icase)
+    {
+#ifdef RE_ENABLE_I18N
+      if (dfa->mb_cur_max > 1)
+	{
+	  while (1)
+	    {
+	      ret = build_wcs_upper_buffer (pstr);
+	      if (BE (ret != REG_NOERROR, 0))
+		return ret;
+	      if (pstr->valid_raw_len >= len)
+		break;
+	      if (pstr->bufs_len > pstr->valid_len + dfa->mb_cur_max)
+		break;
+	      ret = re_string_realloc_buffers (pstr, pstr->bufs_len * 2);
+	      if (BE (ret != REG_NOERROR, 0))
+		return ret;
+	    }
+	}
+      else
+#endif /* RE_ENABLE_I18N  */
+	build_upper_buffer (pstr);
+    }
+  else
+    {
+#ifdef RE_ENABLE_I18N
+      if (dfa->mb_cur_max > 1)
+	build_wcs_buffer (pstr);
+      else
+#endif /* RE_ENABLE_I18N  */
+	{
+	  if (trans != NULL)
+	    re_string_translate_buffer (pstr);
+	  else
+	    {
+	      pstr->valid_len = pstr->bufs_len;
+	      pstr->valid_raw_len = pstr->bufs_len;
+	    }
+	}
+    }
+
+  return REG_NOERROR;
+}
+
+/* Helper functions for re_string_allocate, and re_string_construct.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+re_string_realloc_buffers (re_string_t *pstr, Idx new_buf_len)
+{
+#ifdef RE_ENABLE_I18N
+  if (pstr->mb_cur_max > 1)
+    {
+      wint_t *new_wcs;
+
+      /* Avoid overflow in realloc.  */
+      const size_t max_object_size = MAX (sizeof (wint_t), sizeof (Idx));
+      if (BE (MIN (IDX_MAX, SIZE_MAX / max_object_size) < new_buf_len, 0))
+	return REG_ESPACE;
+
+      new_wcs = re_realloc (pstr->wcs, wint_t, new_buf_len);
+      if (BE (new_wcs == NULL, 0))
+	return REG_ESPACE;
+      pstr->wcs = new_wcs;
+      if (pstr->offsets != NULL)
+	{
+	  Idx *new_offsets = re_realloc (pstr->offsets, Idx, new_buf_len);
+	  if (BE (new_offsets == NULL, 0))
+	    return REG_ESPACE;
+	  pstr->offsets = new_offsets;
+	}
+    }
+#endif /* RE_ENABLE_I18N  */
+  if (pstr->mbs_allocated)
+    {
+      unsigned char *new_mbs = re_realloc (pstr->mbs, unsigned char,
+					   new_buf_len);
+      if (BE (new_mbs == NULL, 0))
+	return REG_ESPACE;
+      pstr->mbs = new_mbs;
+    }
+  pstr->bufs_len = new_buf_len;
+  return REG_NOERROR;
+}
+
+
+static void
+re_string_construct_common (const char *str, Idx len, re_string_t *pstr,
+			    RE_TRANSLATE_TYPE trans, bool icase,
+			    const re_dfa_t *dfa)
+{
+  pstr->raw_mbs = (const unsigned char *) str;
+  pstr->len = len;
+  pstr->raw_len = len;
+  pstr->trans = trans;
+  pstr->icase = icase;
+  pstr->mbs_allocated = (trans != NULL || icase);
+  pstr->mb_cur_max = dfa->mb_cur_max;
+  pstr->is_utf8 = dfa->is_utf8;
+  pstr->map_notascii = dfa->map_notascii;
+  pstr->stop = pstr->len;
+  pstr->raw_stop = pstr->stop;
+}
+
+#ifdef RE_ENABLE_I18N
+
+/* Build wide character buffer PSTR->WCS.
+   If the byte sequence of the string are:
+     <mb1>(0), <mb1>(1), <mb2>(0), <mb2>(1), <sb3>
+   Then wide character buffer will be:
+     <wc1>   , WEOF    , <wc2>   , WEOF    , <wc3>
+   We use WEOF for padding, they indicate that the position isn't
+   a first byte of a multibyte character.
+
+   Note that this function assumes PSTR->VALID_LEN elements are already
+   built and starts from PSTR->VALID_LEN.  */
+
+static void
+build_wcs_buffer (re_string_t *pstr)
+{
+#ifdef _LIBC
+  unsigned char buf[MB_LEN_MAX];
+  assert (MB_LEN_MAX >= pstr->mb_cur_max);
+#else
+  unsigned char buf[64];
+#endif
+  mbstate_t prev_st;
+  Idx byte_idx, end_idx, remain_len;
+  size_t mbclen;
+
+  /* Build the buffers from pstr->valid_len to either pstr->len or
+     pstr->bufs_len.  */
+  end_idx = (pstr->bufs_len > pstr->len) ? pstr->len : pstr->bufs_len;
+  for (byte_idx = pstr->valid_len; byte_idx < end_idx;)
+    {
+      wchar_t wc;
+      const char *p;
+
+      remain_len = end_idx - byte_idx;
+      prev_st = pstr->cur_state;
+      /* Apply the translation if we need.  */
+      if (BE (pstr->trans != NULL, 0))
+	{
+	  int i, ch;
+
+	  for (i = 0; i < pstr->mb_cur_max && i < remain_len; ++i)
+	    {
+	      ch = pstr->raw_mbs [pstr->raw_mbs_idx + byte_idx + i];
+	      buf[i] = pstr->mbs[byte_idx + i] = pstr->trans[ch];
+	    }
+	  p = (const char *) buf;
+	}
+      else
+	p = (const char *) pstr->raw_mbs + pstr->raw_mbs_idx + byte_idx;
+      mbclen = __mbrtowc (&wc, p, remain_len, &pstr->cur_state);
+      if (BE (mbclen == (size_t) -1 || mbclen == 0
+	      || (mbclen == (size_t) -2 && pstr->bufs_len >= pstr->len), 0))
+	{
+	  /* We treat these cases as a singlebyte character.  */
+	  mbclen = 1;
+	  wc = (wchar_t) pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx];
+	  if (BE (pstr->trans != NULL, 0))
+	    wc = pstr->trans[wc];
+	  pstr->cur_state = prev_st;
+	}
+      else if (BE (mbclen == (size_t) -2, 0))
+	{
+	  /* The buffer doesn't have enough space, finish to build.  */
+	  pstr->cur_state = prev_st;
+	  break;
+	}
+
+      /* Write wide character and padding.  */
+      pstr->wcs[byte_idx++] = wc;
+      /* Write paddings.  */
+      for (remain_len = byte_idx + mbclen - 1; byte_idx < remain_len ;)
+	pstr->wcs[byte_idx++] = WEOF;
+    }
+  pstr->valid_len = byte_idx;
+  pstr->valid_raw_len = byte_idx;
+}
+
+/* Build wide character buffer PSTR->WCS like build_wcs_buffer,
+   but for REG_ICASE.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+build_wcs_upper_buffer (re_string_t *pstr)
+{
+  mbstate_t prev_st;
+  Idx src_idx, byte_idx, end_idx, remain_len;
+  size_t mbclen;
+#ifdef _LIBC
+  char buf[MB_LEN_MAX];
+  assert (MB_LEN_MAX >= pstr->mb_cur_max);
+#else
+  char buf[64];
+#endif
+
+  byte_idx = pstr->valid_len;
+  end_idx = (pstr->bufs_len > pstr->len) ? pstr->len : pstr->bufs_len;
+
+  /* The following optimization assumes that ASCII characters can be
+     mapped to wide characters with a simple cast.  */
+  if (! pstr->map_notascii && pstr->trans == NULL && !pstr->offsets_needed)
+    {
+      while (byte_idx < end_idx)
+	{
+	  wchar_t wc;
+
+	  if (isascii (pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx])
+	      && mbsinit (&pstr->cur_state))
+	    {
+	      /* In case of a singlebyte character.  */
+	      pstr->mbs[byte_idx]
+		= toupper (pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx]);
+	      /* The next step uses the assumption that wchar_t is encoded
+		 ASCII-safe: all ASCII values can be converted like this.  */
+	      pstr->wcs[byte_idx] = (wchar_t) pstr->mbs[byte_idx];
+	      ++byte_idx;
+	      continue;
+	    }
+
+	  remain_len = end_idx - byte_idx;
+	  prev_st = pstr->cur_state;
+	  mbclen = __mbrtowc (&wc,
+			      ((const char *) pstr->raw_mbs + pstr->raw_mbs_idx
+			       + byte_idx), remain_len, &pstr->cur_state);
+	  if (BE (mbclen < (size_t) -2, 1))
+	    {
+	      wchar_t wcu = __towupper (wc);
+	      if (wcu != wc)
+		{
+		  size_t mbcdlen;
+
+		  mbcdlen = __wcrtomb (buf, wcu, &prev_st);
+		  if (BE (mbclen == mbcdlen, 1))
+		    memcpy (pstr->mbs + byte_idx, buf, mbclen);
+		  else
+		    {
+		      src_idx = byte_idx;
+		      goto offsets_needed;
+		    }
+		}
+	      else
+		memcpy (pstr->mbs + byte_idx,
+			pstr->raw_mbs + pstr->raw_mbs_idx + byte_idx, mbclen);
+	      pstr->wcs[byte_idx++] = wcu;
+	      /* Write paddings.  */
+	      for (remain_len = byte_idx + mbclen - 1; byte_idx < remain_len ;)
+		pstr->wcs[byte_idx++] = WEOF;
+	    }
+	  else if (mbclen == (size_t) -1 || mbclen == 0
+		   || (mbclen == (size_t) -2 && pstr->bufs_len >= pstr->len))
+	    {
+	      /* It is an invalid character, an incomplete character
+		 at the end of the string, or '\0'.  Just use the byte.  */
+	      int ch = pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx];
+	      pstr->mbs[byte_idx] = ch;
+	      /* And also cast it to wide char.  */
+	      pstr->wcs[byte_idx++] = (wchar_t) ch;
+	      if (BE (mbclen == (size_t) -1, 0))
+		pstr->cur_state = prev_st;
+	    }
+	  else
+	    {
+	      /* The buffer doesn't have enough space, finish to build.  */
+	      pstr->cur_state = prev_st;
+	      break;
+	    }
+	}
+      pstr->valid_len = byte_idx;
+      pstr->valid_raw_len = byte_idx;
+      return REG_NOERROR;
+    }
+  else
+    for (src_idx = pstr->valid_raw_len; byte_idx < end_idx;)
+      {
+	wchar_t wc;
+	const char *p;
+      offsets_needed:
+	remain_len = end_idx - byte_idx;
+	prev_st = pstr->cur_state;
+	if (BE (pstr->trans != NULL, 0))
+	  {
+	    int i, ch;
+
+	    for (i = 0; i < pstr->mb_cur_max && i < remain_len; ++i)
+	      {
+		ch = pstr->raw_mbs [pstr->raw_mbs_idx + src_idx + i];
+		buf[i] = pstr->trans[ch];
+	      }
+	    p = (const char *) buf;
+	  }
+	else
+	  p = (const char *) pstr->raw_mbs + pstr->raw_mbs_idx + src_idx;
+	mbclen = __mbrtowc (&wc, p, remain_len, &pstr->cur_state);
+	if (BE (mbclen < (size_t) -2, 1))
+	  {
+	    wchar_t wcu = __towupper (wc);
+	    if (wcu != wc)
+	      {
+		size_t mbcdlen;
+
+		mbcdlen = __wcrtomb ((char *) buf, wcu, &prev_st);
+		if (BE (mbclen == mbcdlen, 1))
+		  memcpy (pstr->mbs + byte_idx, buf, mbclen);
+		else if (mbcdlen != (size_t) -1)
+		  {
+		    size_t i;
+
+		    if (byte_idx + mbcdlen > pstr->bufs_len)
+		      {
+			pstr->cur_state = prev_st;
+			break;
+		      }
+
+		    if (pstr->offsets == NULL)
+		      {
+			pstr->offsets = re_malloc (Idx, pstr->bufs_len);
+
+			if (pstr->offsets == NULL)
+			  return REG_ESPACE;
+		      }
+		    if (!pstr->offsets_needed)
+		      {
+			for (i = 0; i < (size_t) byte_idx; ++i)
+			  pstr->offsets[i] = i;
+			pstr->offsets_needed = 1;
+		      }
+
+		    memcpy (pstr->mbs + byte_idx, buf, mbcdlen);
+		    pstr->wcs[byte_idx] = wcu;
+		    pstr->offsets[byte_idx] = src_idx;
+		    for (i = 1; i < mbcdlen; ++i)
+		      {
+			pstr->offsets[byte_idx + i]
+			  = src_idx + (i < mbclen ? i : mbclen - 1);
+			pstr->wcs[byte_idx + i] = WEOF;
+		      }
+		    pstr->len += mbcdlen - mbclen;
+		    if (pstr->raw_stop > src_idx)
+		      pstr->stop += mbcdlen - mbclen;
+		    end_idx = (pstr->bufs_len > pstr->len)
+			      ? pstr->len : pstr->bufs_len;
+		    byte_idx += mbcdlen;
+		    src_idx += mbclen;
+		    continue;
+		  }
+		else
+		  memcpy (pstr->mbs + byte_idx, p, mbclen);
+	      }
+	    else
+	      memcpy (pstr->mbs + byte_idx, p, mbclen);
+
+	    if (BE (pstr->offsets_needed != 0, 0))
+	      {
+		size_t i;
+		for (i = 0; i < mbclen; ++i)
+		  pstr->offsets[byte_idx + i] = src_idx + i;
+	      }
+	    src_idx += mbclen;
+
+	    pstr->wcs[byte_idx++] = wcu;
+	    /* Write paddings.  */
+	    for (remain_len = byte_idx + mbclen - 1; byte_idx < remain_len ;)
+	      pstr->wcs[byte_idx++] = WEOF;
+	  }
+	else if (mbclen == (size_t) -1 || mbclen == 0
+		 || (mbclen == (size_t) -2 && pstr->bufs_len >= pstr->len))
+	  {
+	    /* It is an invalid character or '\0'.  Just use the byte.  */
+	    int ch = pstr->raw_mbs[pstr->raw_mbs_idx + src_idx];
+
+	    if (BE (pstr->trans != NULL, 0))
+	      ch = pstr->trans [ch];
+	    pstr->mbs[byte_idx] = ch;
+
+	    if (BE (pstr->offsets_needed != 0, 0))
+	      pstr->offsets[byte_idx] = src_idx;
+	    ++src_idx;
+
+	    /* And also cast it to wide char.  */
+	    pstr->wcs[byte_idx++] = (wchar_t) ch;
+	    if (BE (mbclen == (size_t) -1, 0))
+	      pstr->cur_state = prev_st;
+	  }
+	else
+	  {
+	    /* The buffer doesn't have enough space, finish to build.  */
+	    pstr->cur_state = prev_st;
+	    break;
+	  }
+      }
+  pstr->valid_len = byte_idx;
+  pstr->valid_raw_len = src_idx;
+  return REG_NOERROR;
+}
+
+/* Skip characters until the index becomes greater than NEW_RAW_IDX.
+   Return the index.  */
+
+static Idx
+re_string_skip_chars (re_string_t *pstr, Idx new_raw_idx, wint_t *last_wc)
+{
+  mbstate_t prev_st;
+  Idx rawbuf_idx;
+  size_t mbclen;
+  wint_t wc = WEOF;
+
+  /* Skip the characters which are not necessary to check.  */
+  for (rawbuf_idx = pstr->raw_mbs_idx + pstr->valid_raw_len;
+       rawbuf_idx < new_raw_idx;)
+    {
+      wchar_t wc2;
+      Idx remain_len = pstr->raw_len - rawbuf_idx;
+      prev_st = pstr->cur_state;
+      mbclen = __mbrtowc (&wc2, (const char *) pstr->raw_mbs + rawbuf_idx,
+			  remain_len, &pstr->cur_state);
+      if (BE (mbclen == (size_t) -2 || mbclen == (size_t) -1 || mbclen == 0, 0))
+	{
+	  /* We treat these cases as a single byte character.  */
+	  if (mbclen == 0 || remain_len == 0)
+	    wc = L'\0';
+	  else
+	    wc = *(unsigned char *) (pstr->raw_mbs + rawbuf_idx);
+	  mbclen = 1;
+	  pstr->cur_state = prev_st;
+	}
+      else
+	wc = wc2;
+      /* Then proceed the next character.  */
+      rawbuf_idx += mbclen;
+    }
+  *last_wc = wc;
+  return rawbuf_idx;
+}
+#endif /* RE_ENABLE_I18N  */
+
+/* Build the buffer PSTR->MBS, and apply the translation if we need.
+   This function is used in case of REG_ICASE.  */
+
+static void
+build_upper_buffer (re_string_t *pstr)
+{
+  Idx char_idx, end_idx;
+  end_idx = (pstr->bufs_len > pstr->len) ? pstr->len : pstr->bufs_len;
+
+  for (char_idx = pstr->valid_len; char_idx < end_idx; ++char_idx)
+    {
+      int ch = pstr->raw_mbs[pstr->raw_mbs_idx + char_idx];
+      if (BE (pstr->trans != NULL, 0))
+	ch = pstr->trans[ch];
+      pstr->mbs[char_idx] = toupper (ch);
+    }
+  pstr->valid_len = char_idx;
+  pstr->valid_raw_len = char_idx;
+}
+
+/* Apply TRANS to the buffer in PSTR.  */
+
+static void
+re_string_translate_buffer (re_string_t *pstr)
+{
+  Idx buf_idx, end_idx;
+  end_idx = (pstr->bufs_len > pstr->len) ? pstr->len : pstr->bufs_len;
+
+  for (buf_idx = pstr->valid_len; buf_idx < end_idx; ++buf_idx)
+    {
+      int ch = pstr->raw_mbs[pstr->raw_mbs_idx + buf_idx];
+      pstr->mbs[buf_idx] = pstr->trans[ch];
+    }
+
+  pstr->valid_len = buf_idx;
+  pstr->valid_raw_len = buf_idx;
+}
+
+/* This function re-construct the buffers.
+   Concretely, convert to wide character in case of pstr->mb_cur_max > 1,
+   convert to upper case in case of REG_ICASE, apply translation.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+re_string_reconstruct (re_string_t *pstr, Idx idx, int eflags)
+{
+  Idx offset;
+
+  if (BE (pstr->raw_mbs_idx <= idx, 0))
+    offset = idx - pstr->raw_mbs_idx;
+  else
+    {
+      /* Reset buffer.  */
+#ifdef RE_ENABLE_I18N
+      if (pstr->mb_cur_max > 1)
+	memset (&pstr->cur_state, '\0', sizeof (mbstate_t));
+#endif /* RE_ENABLE_I18N */
+      pstr->len = pstr->raw_len;
+      pstr->stop = pstr->raw_stop;
+      pstr->valid_len = 0;
+      pstr->raw_mbs_idx = 0;
+      pstr->valid_raw_len = 0;
+      pstr->offsets_needed = 0;
+      pstr->tip_context = ((eflags & REG_NOTBOL) ? CONTEXT_BEGBUF
+			   : CONTEXT_NEWLINE | CONTEXT_BEGBUF);
+      if (!pstr->mbs_allocated)
+	pstr->mbs = (unsigned char *) pstr->raw_mbs;
+      offset = idx;
+    }
+
+  if (BE (offset != 0, 1))
+    {
+      /* Should the already checked characters be kept?  */
+      if (BE (offset < pstr->valid_raw_len, 1))
+	{
+	  /* Yes, move them to the front of the buffer.  */
+#ifdef RE_ENABLE_I18N
+	  if (BE (pstr->offsets_needed, 0))
+	    {
+	      Idx low = 0, high = pstr->valid_len, mid;
+	      do
+		{
+		  mid = (high + low) / 2;
+		  if (pstr->offsets[mid] > offset)
+		    high = mid;
+		  else if (pstr->offsets[mid] < offset)
+		    low = mid + 1;
+		  else
+		    break;
+		}
+	      while (low < high);
+	      if (pstr->offsets[mid] < offset)
+		++mid;
+	      pstr->tip_context = re_string_context_at (pstr, mid - 1,
+							eflags);
+	      /* This can be quite complicated, so handle specially
+		 only the common and easy case where the character with
+		 different length representation of lower and upper
+		 case is present at or after offset.  */
+	      if (pstr->valid_len > offset
+		  && mid == offset && pstr->offsets[mid] == offset)
+		{
+		  memmove (pstr->wcs, pstr->wcs + offset,
+			   (pstr->valid_len - offset) * sizeof (wint_t));
+		  memmove (pstr->mbs, pstr->mbs + offset, pstr->valid_len - offset);
+		  pstr->valid_len -= offset;
+		  pstr->valid_raw_len -= offset;
+		  for (low = 0; low < pstr->valid_len; low++)
+		    pstr->offsets[low] = pstr->offsets[low + offset] - offset;
+		}
+	      else
+		{
+		  /* Otherwise, just find out how long the partial multibyte
+		     character at offset is and fill it with WEOF/255.  */
+		  pstr->len = pstr->raw_len - idx + offset;
+		  pstr->stop = pstr->raw_stop - idx + offset;
+		  pstr->offsets_needed = 0;
+		  while (mid > 0 && pstr->offsets[mid - 1] == offset)
+		    --mid;
+		  while (mid < pstr->valid_len)
+		    if (pstr->wcs[mid] != WEOF)
+		      break;
+		    else
+		      ++mid;
+		  if (mid == pstr->valid_len)
+		    pstr->valid_len = 0;
+		  else
+		    {
+		      pstr->valid_len = pstr->offsets[mid] - offset;
+		      if (pstr->valid_len)
+			{
+			  for (low = 0; low < pstr->valid_len; ++low)
+			    pstr->wcs[low] = WEOF;
+			  memset (pstr->mbs, 255, pstr->valid_len);
+			}
+		    }
+		  pstr->valid_raw_len = pstr->valid_len;
+		}
+	    }
+	  else
+#endif
+	    {
+	      pstr->tip_context = re_string_context_at (pstr, offset - 1,
+							eflags);
+#ifdef RE_ENABLE_I18N
+	      if (pstr->mb_cur_max > 1)
+		memmove (pstr->wcs, pstr->wcs + offset,
+			 (pstr->valid_len - offset) * sizeof (wint_t));
+#endif /* RE_ENABLE_I18N */
+	      if (BE (pstr->mbs_allocated, 0))
+		memmove (pstr->mbs, pstr->mbs + offset,
+			 pstr->valid_len - offset);
+	      pstr->valid_len -= offset;
+	      pstr->valid_raw_len -= offset;
+#if defined DEBUG && DEBUG
+	      assert (pstr->valid_len > 0);
+#endif
+	    }
+	}
+      else
+	{
+#ifdef RE_ENABLE_I18N
+	  /* No, skip all characters until IDX.  */
+	  Idx prev_valid_len = pstr->valid_len;
+
+	  if (BE (pstr->offsets_needed, 0))
+	    {
+	      pstr->len = pstr->raw_len - idx + offset;
+	      pstr->stop = pstr->raw_stop - idx + offset;
+	      pstr->offsets_needed = 0;
+	    }
+#endif
+	  pstr->valid_len = 0;
+#ifdef RE_ENABLE_I18N
+	  if (pstr->mb_cur_max > 1)
+	    {
+	      Idx wcs_idx;
+	      wint_t wc = WEOF;
+
+	      if (pstr->is_utf8)
+		{
+		  const unsigned char *raw, *p, *end;
+
+		  /* Special case UTF-8.  Multi-byte chars start with any
+		     byte other than 0x80 - 0xbf.  */
+		  raw = pstr->raw_mbs + pstr->raw_mbs_idx;
+		  end = raw + (offset - pstr->mb_cur_max);
+		  if (end < pstr->raw_mbs)
+		    end = pstr->raw_mbs;
+		  p = raw + offset - 1;
+#ifdef _LIBC
+		  /* We know the wchar_t encoding is UCS4, so for the simple
+		     case, ASCII characters, skip the conversion step.  */
+		  if (isascii (*p) && BE (pstr->trans == NULL, 1))
+		    {
+		      memset (&pstr->cur_state, '\0', sizeof (mbstate_t));
+		      /* pstr->valid_len = 0; */
+		      wc = (wchar_t) *p;
+		    }
+		  else
+#endif
+		    for (; p >= end; --p)
+		      if ((*p & 0xc0) != 0x80)
+			{
+			  mbstate_t cur_state;
+			  wchar_t wc2;
+			  Idx mlen = raw + pstr->len - p;
+			  unsigned char buf[6];
+			  size_t mbclen;
+
+			  const unsigned char *pp = p;
+			  if (BE (pstr->trans != NULL, 0))
+			    {
+			      int i = mlen < 6 ? mlen : 6;
+			      while (--i >= 0)
+				buf[i] = pstr->trans[p[i]];
+			      pp = buf;
+			    }
+			  /* XXX Don't use mbrtowc, we know which conversion
+			     to use (UTF-8 -> UCS4).  */
+			  memset (&cur_state, 0, sizeof (cur_state));
+			  mbclen = __mbrtowc (&wc2, (const char *) pp, mlen,
+					      &cur_state);
+			  if (raw + offset - p <= mbclen
+			      && mbclen < (size_t) -2)
+			    {
+			      memset (&pstr->cur_state, '\0',
+				      sizeof (mbstate_t));
+			      pstr->valid_len = mbclen - (raw + offset - p);
+			      wc = wc2;
+			    }
+			  break;
+			}
+		}
+
+	      if (wc == WEOF)
+		pstr->valid_len = re_string_skip_chars (pstr, idx, &wc) - idx;
+	      if (wc == WEOF)
+		pstr->tip_context
+		  = re_string_context_at (pstr, prev_valid_len - 1, eflags);
+	      else
+		pstr->tip_context = ((BE (pstr->word_ops_used != 0, 0)
+				      && IS_WIDE_WORD_CHAR (wc))
+				     ? CONTEXT_WORD
+				     : ((IS_WIDE_NEWLINE (wc)
+					 && pstr->newline_anchor)
+					? CONTEXT_NEWLINE : 0));
+	      if (BE (pstr->valid_len, 0))
+		{
+		  for (wcs_idx = 0; wcs_idx < pstr->valid_len; ++wcs_idx)
+		    pstr->wcs[wcs_idx] = WEOF;
+		  if (pstr->mbs_allocated)
+		    memset (pstr->mbs, 255, pstr->valid_len);
+		}
+	      pstr->valid_raw_len = pstr->valid_len;
+	    }
+	  else
+#endif /* RE_ENABLE_I18N */
+	    {
+	      int c = pstr->raw_mbs[pstr->raw_mbs_idx + offset - 1];
+	      pstr->valid_raw_len = 0;
+	      if (pstr->trans)
+		c = pstr->trans[c];
+	      pstr->tip_context = (bitset_contain (pstr->word_char, c)
+				   ? CONTEXT_WORD
+				   : ((IS_NEWLINE (c) && pstr->newline_anchor)
+				      ? CONTEXT_NEWLINE : 0));
+	    }
+	}
+      if (!BE (pstr->mbs_allocated, 0))
+	pstr->mbs += offset;
+    }
+  pstr->raw_mbs_idx = idx;
+  pstr->len -= offset;
+  pstr->stop -= offset;
+
+  /* Then build the buffers.  */
+#ifdef RE_ENABLE_I18N
+  if (pstr->mb_cur_max > 1)
+    {
+      if (pstr->icase)
+	{
+	  reg_errcode_t ret = build_wcs_upper_buffer (pstr);
+	  if (BE (ret != REG_NOERROR, 0))
+	    return ret;
+	}
+      else
+	build_wcs_buffer (pstr);
+    }
+  else
+#endif /* RE_ENABLE_I18N */
+    if (BE (pstr->mbs_allocated, 0))
+      {
+	if (pstr->icase)
+	  build_upper_buffer (pstr);
+	else if (pstr->trans != NULL)
+	  re_string_translate_buffer (pstr);
+      }
+    else
+      pstr->valid_len = pstr->len;
+
+  pstr->cur_idx = 0;
+  return REG_NOERROR;
+}
+
+static unsigned char
+__attribute__ ((pure))
+re_string_peek_byte_case (const re_string_t *pstr, Idx idx)
+{
+  int ch;
+  Idx off;
+
+  /* Handle the common (easiest) cases first.  */
+  if (BE (!pstr->mbs_allocated, 1))
+    return re_string_peek_byte (pstr, idx);
+
+#ifdef RE_ENABLE_I18N
+  if (pstr->mb_cur_max > 1
+      && ! re_string_is_single_byte_char (pstr, pstr->cur_idx + idx))
+    return re_string_peek_byte (pstr, idx);
+#endif
+
+  off = pstr->cur_idx + idx;
+#ifdef RE_ENABLE_I18N
+  if (pstr->offsets_needed)
+    off = pstr->offsets[off];
+#endif
+
+  ch = pstr->raw_mbs[pstr->raw_mbs_idx + off];
+
+#ifdef RE_ENABLE_I18N
+  /* Ensure that e.g. for tr_TR.UTF-8 BACKSLASH DOTLESS SMALL LETTER I
+     this function returns CAPITAL LETTER I instead of first byte of
+     DOTLESS SMALL LETTER I.  The latter would confuse the parser,
+     since peek_byte_case doesn't advance cur_idx in any way.  */
+  if (pstr->offsets_needed && !isascii (ch))
+    return re_string_peek_byte (pstr, idx);
+#endif
+
+  return ch;
+}
+
+static unsigned char
+re_string_fetch_byte_case (re_string_t *pstr)
+{
+  if (BE (!pstr->mbs_allocated, 1))
+    return re_string_fetch_byte (pstr);
+
+#ifdef RE_ENABLE_I18N
+  if (pstr->offsets_needed)
+    {
+      Idx off;
+      int ch;
+
+      /* For tr_TR.UTF-8 [[:islower:]] there is
+	 [[: CAPITAL LETTER I WITH DOT lower:]] in mbs.  Skip
+	 in that case the whole multi-byte character and return
+	 the original letter.  On the other side, with
+	 [[: DOTLESS SMALL LETTER I return [[:I, as doing
+	 anything else would complicate things too much.  */
+
+      if (!re_string_first_byte (pstr, pstr->cur_idx))
+	return re_string_fetch_byte (pstr);
+
+      off = pstr->offsets[pstr->cur_idx];
+      ch = pstr->raw_mbs[pstr->raw_mbs_idx + off];
+
+      if (! isascii (ch))
+	return re_string_fetch_byte (pstr);
+
+      re_string_skip_bytes (pstr,
+			    re_string_char_size_at (pstr, pstr->cur_idx));
+      return ch;
+    }
+#endif
+
+  return pstr->raw_mbs[pstr->raw_mbs_idx + pstr->cur_idx++];
+}
+
+static void
+re_string_destruct (re_string_t *pstr)
+{
+#ifdef RE_ENABLE_I18N
+  re_free (pstr->wcs);
+  re_free (pstr->offsets);
+#endif /* RE_ENABLE_I18N  */
+  if (pstr->mbs_allocated)
+    re_free (pstr->mbs);
+}
+
+/* Return the context at IDX in INPUT.  */
+
+static unsigned int
+re_string_context_at (const re_string_t *input, Idx idx, int eflags)
+{
+  int c;
+  if (BE (idx < 0, 0))
+    /* In this case, we use the value stored in input->tip_context,
+       since we can't know the character in input->mbs[-1] here.  */
+    return input->tip_context;
+  if (BE (idx == input->len, 0))
+    return ((eflags & REG_NOTEOL) ? CONTEXT_ENDBUF
+	    : CONTEXT_NEWLINE | CONTEXT_ENDBUF);
+#ifdef RE_ENABLE_I18N
+  if (input->mb_cur_max > 1)
+    {
+      wint_t wc;
+      Idx wc_idx = idx;
+      while(input->wcs[wc_idx] == WEOF)
+	{
+#if defined DEBUG && DEBUG
+	  /* It must not happen.  */
+	  assert (wc_idx >= 0);
+#endif
+	  --wc_idx;
+	  if (wc_idx < 0)
+	    return input->tip_context;
+	}
+      wc = input->wcs[wc_idx];
+      if (BE (input->word_ops_used != 0, 0) && IS_WIDE_WORD_CHAR (wc))
+	return CONTEXT_WORD;
+      return (IS_WIDE_NEWLINE (wc) && input->newline_anchor
+	      ? CONTEXT_NEWLINE : 0);
+    }
+  else
+#endif
+    {
+      c = re_string_byte_at (input, idx);
+      if (bitset_contain (input->word_char, c))
+	return CONTEXT_WORD;
+      return IS_NEWLINE (c) && input->newline_anchor ? CONTEXT_NEWLINE : 0;
+    }
+}
+
+/* Functions for set operation.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+re_node_set_alloc (re_node_set *set, Idx size)
+{
+  set->alloc = size;
+  set->nelem = 0;
+  set->elems = re_malloc (Idx, size);
+  if (BE (set->elems == NULL, 0) && (MALLOC_0_IS_NONNULL || size != 0))
+    return REG_ESPACE;
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+re_node_set_init_1 (re_node_set *set, Idx elem)
+{
+  set->alloc = 1;
+  set->nelem = 1;
+  set->elems = re_malloc (Idx, 1);
+  if (BE (set->elems == NULL, 0))
+    {
+      set->alloc = set->nelem = 0;
+      return REG_ESPACE;
+    }
+  set->elems[0] = elem;
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+re_node_set_init_2 (re_node_set *set, Idx elem1, Idx elem2)
+{
+  set->alloc = 2;
+  set->elems = re_malloc (Idx, 2);
+  if (BE (set->elems == NULL, 0))
+    return REG_ESPACE;
+  if (elem1 == elem2)
+    {
+      set->nelem = 1;
+      set->elems[0] = elem1;
+    }
+  else
+    {
+      set->nelem = 2;
+      if (elem1 < elem2)
+	{
+	  set->elems[0] = elem1;
+	  set->elems[1] = elem2;
+	}
+      else
+	{
+	  set->elems[0] = elem2;
+	  set->elems[1] = elem1;
+	}
+    }
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+re_node_set_init_copy (re_node_set *dest, const re_node_set *src)
+{
+  dest->nelem = src->nelem;
+  if (src->nelem > 0)
+    {
+      dest->alloc = dest->nelem;
+      dest->elems = re_malloc (Idx, dest->alloc);
+      if (BE (dest->elems == NULL, 0))
+	{
+	  dest->alloc = dest->nelem = 0;
+	  return REG_ESPACE;
+	}
+      memcpy (dest->elems, src->elems, src->nelem * sizeof (Idx));
+    }
+  else
+    re_node_set_init_empty (dest);
+  return REG_NOERROR;
+}
+
+/* Calculate the intersection of the sets SRC1 and SRC2. And merge it to
+   DEST. Return value indicate the error code or REG_NOERROR if succeeded.
+   Note: We assume dest->elems is NULL, when dest->alloc is 0.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+re_node_set_add_intersect (re_node_set *dest, const re_node_set *src1,
+			   const re_node_set *src2)
+{
+  Idx i1, i2, is, id, delta, sbase;
+  if (src1->nelem == 0 || src2->nelem == 0)
+    return REG_NOERROR;
+
+  /* We need dest->nelem + 2 * elems_in_intersection; this is a
+     conservative estimate.  */
+  if (src1->nelem + src2->nelem + dest->nelem > dest->alloc)
+    {
+      Idx new_alloc = src1->nelem + src2->nelem + dest->alloc;
+      Idx *new_elems = re_realloc (dest->elems, Idx, new_alloc);
+      if (BE (new_elems == NULL, 0))
+	return REG_ESPACE;
+      dest->elems = new_elems;
+      dest->alloc = new_alloc;
+    }
+
+  /* Find the items in the intersection of SRC1 and SRC2, and copy
+     into the top of DEST those that are not already in DEST itself.  */
+  sbase = dest->nelem + src1->nelem + src2->nelem;
+  i1 = src1->nelem - 1;
+  i2 = src2->nelem - 1;
+  id = dest->nelem - 1;
+  for (;;)
+    {
+      if (src1->elems[i1] == src2->elems[i2])
+	{
+	  /* Try to find the item in DEST.  Maybe we could binary search?  */
+	  while (id >= 0 && dest->elems[id] > src1->elems[i1])
+	    --id;
+
+	  if (id < 0 || dest->elems[id] != src1->elems[i1])
+            dest->elems[--sbase] = src1->elems[i1];
+
+	  if (--i1 < 0 || --i2 < 0)
+	    break;
+	}
+
+      /* Lower the highest of the two items.  */
+      else if (src1->elems[i1] < src2->elems[i2])
+	{
+	  if (--i2 < 0)
+	    break;
+	}
+      else
+	{
+	  if (--i1 < 0)
+	    break;
+	}
+    }
+
+  id = dest->nelem - 1;
+  is = dest->nelem + src1->nelem + src2->nelem - 1;
+  delta = is - sbase + 1;
+
+  /* Now copy.  When DELTA becomes zero, the remaining
+     DEST elements are already in place; this is more or
+     less the same loop that is in re_node_set_merge.  */
+  dest->nelem += delta;
+  if (delta > 0 && id >= 0)
+    for (;;)
+      {
+	if (dest->elems[is] > dest->elems[id])
+	  {
+	    /* Copy from the top.  */
+	    dest->elems[id + delta--] = dest->elems[is--];
+	    if (delta == 0)
+	      break;
+	  }
+	else
+	  {
+	    /* Slide from the bottom.  */
+	    dest->elems[id + delta] = dest->elems[id];
+	    if (--id < 0)
+	      break;
+	  }
+      }
+
+  /* Copy remaining SRC elements.  */
+  memcpy (dest->elems, dest->elems + sbase, delta * sizeof (Idx));
+
+  return REG_NOERROR;
+}
+
+/* Calculate the union set of the sets SRC1 and SRC2. And store it to
+   DEST. Return value indicate the error code or REG_NOERROR if succeeded.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+re_node_set_init_union (re_node_set *dest, const re_node_set *src1,
+			const re_node_set *src2)
+{
+  Idx i1, i2, id;
+  if (src1 != NULL && src1->nelem > 0 && src2 != NULL && src2->nelem > 0)
+    {
+      dest->alloc = src1->nelem + src2->nelem;
+      dest->elems = re_malloc (Idx, dest->alloc);
+      if (BE (dest->elems == NULL, 0))
+	return REG_ESPACE;
+    }
+  else
+    {
+      if (src1 != NULL && src1->nelem > 0)
+	return re_node_set_init_copy (dest, src1);
+      else if (src2 != NULL && src2->nelem > 0)
+	return re_node_set_init_copy (dest, src2);
+      else
+	re_node_set_init_empty (dest);
+      return REG_NOERROR;
+    }
+  for (i1 = i2 = id = 0 ; i1 < src1->nelem && i2 < src2->nelem ;)
+    {
+      if (src1->elems[i1] > src2->elems[i2])
+	{
+	  dest->elems[id++] = src2->elems[i2++];
+	  continue;
+	}
+      if (src1->elems[i1] == src2->elems[i2])
+	++i2;
+      dest->elems[id++] = src1->elems[i1++];
+    }
+  if (i1 < src1->nelem)
+    {
+      memcpy (dest->elems + id, src1->elems + i1,
+	     (src1->nelem - i1) * sizeof (Idx));
+      id += src1->nelem - i1;
+    }
+  else if (i2 < src2->nelem)
+    {
+      memcpy (dest->elems + id, src2->elems + i2,
+	     (src2->nelem - i2) * sizeof (Idx));
+      id += src2->nelem - i2;
+    }
+  dest->nelem = id;
+  return REG_NOERROR;
+}
+
+/* Calculate the union set of the sets DEST and SRC. And store it to
+   DEST. Return value indicate the error code or REG_NOERROR if succeeded.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+re_node_set_merge (re_node_set *dest, const re_node_set *src)
+{
+  Idx is, id, sbase, delta;
+  if (src == NULL || src->nelem == 0)
+    return REG_NOERROR;
+  if (dest->alloc < 2 * src->nelem + dest->nelem)
+    {
+      Idx new_alloc = 2 * (src->nelem + dest->alloc);
+      Idx *new_buffer = re_realloc (dest->elems, Idx, new_alloc);
+      if (BE (new_buffer == NULL, 0))
+	return REG_ESPACE;
+      dest->elems = new_buffer;
+      dest->alloc = new_alloc;
+    }
+
+  if (BE (dest->nelem == 0, 0))
+    {
+      dest->nelem = src->nelem;
+      memcpy (dest->elems, src->elems, src->nelem * sizeof (Idx));
+      return REG_NOERROR;
+    }
+
+  /* Copy into the top of DEST the items of SRC that are not
+     found in DEST.  Maybe we could binary search in DEST?  */
+  for (sbase = dest->nelem + 2 * src->nelem,
+       is = src->nelem - 1, id = dest->nelem - 1; is >= 0 && id >= 0; )
+    {
+      if (dest->elems[id] == src->elems[is])
+	is--, id--;
+      else if (dest->elems[id] < src->elems[is])
+	dest->elems[--sbase] = src->elems[is--];
+      else /* if (dest->elems[id] > src->elems[is]) */
+	--id;
+    }
+
+  if (is >= 0)
+    {
+      /* If DEST is exhausted, the remaining items of SRC must be unique.  */
+      sbase -= is + 1;
+      memcpy (dest->elems + sbase, src->elems, (is + 1) * sizeof (Idx));
+    }
+
+  id = dest->nelem - 1;
+  is = dest->nelem + 2 * src->nelem - 1;
+  delta = is - sbase + 1;
+  if (delta == 0)
+    return REG_NOERROR;
+
+  /* Now copy.  When DELTA becomes zero, the remaining
+     DEST elements are already in place.  */
+  dest->nelem += delta;
+  for (;;)
+    {
+      if (dest->elems[is] > dest->elems[id])
+	{
+	  /* Copy from the top.  */
+	  dest->elems[id + delta--] = dest->elems[is--];
+	  if (delta == 0)
+	    break;
+	}
+      else
+	{
+	  /* Slide from the bottom.  */
+	  dest->elems[id + delta] = dest->elems[id];
+	  if (--id < 0)
+	    {
+	      /* Copy remaining SRC elements.  */
+	      memcpy (dest->elems, dest->elems + sbase,
+		      delta * sizeof (Idx));
+	      break;
+	    }
+	}
+    }
+
+  return REG_NOERROR;
+}
+
+/* Insert the new element ELEM to the re_node_set* SET.
+   SET should not already have ELEM.
+   Return true if successful.  */
+
+static bool
+__attribute_warn_unused_result__
+re_node_set_insert (re_node_set *set, Idx elem)
+{
+  Idx idx;
+  /* In case the set is empty.  */
+  if (set->alloc == 0)
+    return BE (re_node_set_init_1 (set, elem) == REG_NOERROR, 1);
+
+  if (BE (set->nelem, 0) == 0)
+    {
+      /* We already guaranteed above that set->alloc != 0.  */
+      set->elems[0] = elem;
+      ++set->nelem;
+      return true;
+    }
+
+  /* Realloc if we need.  */
+  if (set->alloc == set->nelem)
+    {
+      Idx *new_elems;
+      set->alloc = set->alloc * 2;
+      new_elems = re_realloc (set->elems, Idx, set->alloc);
+      if (BE (new_elems == NULL, 0))
+	return false;
+      set->elems = new_elems;
+    }
+
+  /* Move the elements which follows the new element.  Test the
+     first element separately to skip a check in the inner loop.  */
+  if (elem < set->elems[0])
+    {
+      idx = 0;
+      for (idx = set->nelem; idx > 0; idx--)
+	set->elems[idx] = set->elems[idx - 1];
+    }
+  else
+    {
+      for (idx = set->nelem; set->elems[idx - 1] > elem; idx--)
+	set->elems[idx] = set->elems[idx - 1];
+    }
+
+  /* Insert the new element.  */
+  set->elems[idx] = elem;
+  ++set->nelem;
+  return true;
+}
+
+/* Insert the new element ELEM to the re_node_set* SET.
+   SET should not already have any element greater than or equal to ELEM.
+   Return true if successful.  */
+
+static bool
+__attribute_warn_unused_result__
+re_node_set_insert_last (re_node_set *set, Idx elem)
+{
+  /* Realloc if we need.  */
+  if (set->alloc == set->nelem)
+    {
+      Idx *new_elems;
+      set->alloc = (set->alloc + 1) * 2;
+      new_elems = re_realloc (set->elems, Idx, set->alloc);
+      if (BE (new_elems == NULL, 0))
+	return false;
+      set->elems = new_elems;
+    }
+
+  /* Insert the new element.  */
+  set->elems[set->nelem++] = elem;
+  return true;
+}
+
+/* Compare two node sets SET1 and SET2.
+   Return true if SET1 and SET2 are equivalent.  */
+
+static bool
+__attribute__ ((pure))
+re_node_set_compare (const re_node_set *set1, const re_node_set *set2)
+{
+  Idx i;
+  if (set1 == NULL || set2 == NULL || set1->nelem != set2->nelem)
+    return false;
+  for (i = set1->nelem ; --i >= 0 ; )
+    if (set1->elems[i] != set2->elems[i])
+      return false;
+  return true;
+}
+
+/* Return (idx + 1) if SET contains the element ELEM, return 0 otherwise.  */
+
+static Idx
+__attribute__ ((pure))
+re_node_set_contains (const re_node_set *set, Idx elem)
+{
+  __re_size_t idx, right, mid;
+  if (set->nelem <= 0)
+    return 0;
+
+  /* Binary search the element.  */
+  idx = 0;
+  right = set->nelem - 1;
+  while (idx < right)
+    {
+      mid = (idx + right) / 2;
+      if (set->elems[mid] < elem)
+	idx = mid + 1;
+      else
+	right = mid;
+    }
+  return set->elems[idx] == elem ? idx + 1 : 0;
+}
+
+static void
+re_node_set_remove_at (re_node_set *set, Idx idx)
+{
+  if (idx < 0 || idx >= set->nelem)
+    return;
+  --set->nelem;
+  for (; idx < set->nelem; idx++)
+    set->elems[idx] = set->elems[idx + 1];
+}
+
+
+/* Add the token TOKEN to dfa->nodes, and return the index of the token.
+   Or return -1 if an error occurred.  */
+
+static Idx
+re_dfa_add_node (re_dfa_t *dfa, re_token_t token)
+{
+  if (BE (dfa->nodes_len >= dfa->nodes_alloc, 0))
+    {
+      size_t new_nodes_alloc = dfa->nodes_alloc * 2;
+      Idx *new_nexts, *new_indices;
+      re_node_set *new_edests, *new_eclosures;
+      re_token_t *new_nodes;
+
+      /* Avoid overflows in realloc.  */
+      const size_t max_object_size = MAX (sizeof (re_token_t),
+					  MAX (sizeof (re_node_set),
+					       sizeof (Idx)));
+      if (BE (MIN (IDX_MAX, SIZE_MAX / max_object_size) < new_nodes_alloc, 0))
+	return -1;
+
+      new_nodes = re_realloc (dfa->nodes, re_token_t, new_nodes_alloc);
+      if (BE (new_nodes == NULL, 0))
+	return -1;
+      dfa->nodes = new_nodes;
+      new_nexts = re_realloc (dfa->nexts, Idx, new_nodes_alloc);
+      new_indices = re_realloc (dfa->org_indices, Idx, new_nodes_alloc);
+      new_edests = re_realloc (dfa->edests, re_node_set, new_nodes_alloc);
+      new_eclosures = re_realloc (dfa->eclosures, re_node_set, new_nodes_alloc);
+      if (BE (new_nexts == NULL || new_indices == NULL
+	      || new_edests == NULL || new_eclosures == NULL, 0))
+	{
+	   re_free (new_nexts);
+	   re_free (new_indices);
+	   re_free (new_edests);
+	   re_free (new_eclosures);
+	   return -1;
+	}
+      dfa->nexts = new_nexts;
+      dfa->org_indices = new_indices;
+      dfa->edests = new_edests;
+      dfa->eclosures = new_eclosures;
+      dfa->nodes_alloc = new_nodes_alloc;
+    }
+  dfa->nodes[dfa->nodes_len] = token;
+  dfa->nodes[dfa->nodes_len].constraint = 0;
+#ifdef RE_ENABLE_I18N
+  dfa->nodes[dfa->nodes_len].accept_mb =
+    ((token.type == OP_PERIOD && dfa->mb_cur_max > 1)
+     || token.type == COMPLEX_BRACKET);
+#endif
+  dfa->nexts[dfa->nodes_len] = -1;
+  re_node_set_init_empty (dfa->edests + dfa->nodes_len);
+  re_node_set_init_empty (dfa->eclosures + dfa->nodes_len);
+  return dfa->nodes_len++;
+}
+
+static re_hashval_t
+calc_state_hash (const re_node_set *nodes, unsigned int context)
+{
+  re_hashval_t hash = nodes->nelem + context;
+  Idx i;
+  for (i = 0 ; i < nodes->nelem ; i++)
+    hash += nodes->elems[i];
+  return hash;
+}
+
+/* Search for the state whose node_set is equivalent to NODES.
+   Return the pointer to the state, if we found it in the DFA.
+   Otherwise create the new one and return it.  In case of an error
+   return NULL and set the error code in ERR.
+   Note: - We assume NULL as the invalid state, then it is possible that
+	   return value is NULL and ERR is REG_NOERROR.
+	 - We never return non-NULL value in case of any errors, it is for
+	   optimization.  */
+
+static re_dfastate_t *
+__attribute_warn_unused_result__
+re_acquire_state (reg_errcode_t *err, const re_dfa_t *dfa,
+		  const re_node_set *nodes)
+{
+  re_hashval_t hash;
+  re_dfastate_t *new_state;
+  struct re_state_table_entry *spot;
+  Idx i;
+#if defined GCC_LINT || defined lint
+  /* Suppress bogus uninitialized-variable warnings.  */
+  *err = REG_NOERROR;
+#endif
+  if (BE (nodes->nelem == 0, 0))
+    {
+      *err = REG_NOERROR;
+      return NULL;
+    }
+  hash = calc_state_hash (nodes, 0);
+  spot = dfa->state_table + (hash & dfa->state_hash_mask);
+
+  for (i = 0 ; i < spot->num ; i++)
+    {
+      re_dfastate_t *state = spot->array[i];
+      if (hash != state->hash)
+	continue;
+      if (re_node_set_compare (&state->nodes, nodes))
+	return state;
+    }
+
+  /* There are no appropriate state in the dfa, create the new one.  */
+  new_state = create_ci_newstate (dfa, nodes, hash);
+  if (BE (new_state == NULL, 0))
+    *err = REG_ESPACE;
+
+  return new_state;
+}
+
+/* Search for the state whose node_set is equivalent to NODES and
+   whose context is equivalent to CONTEXT.
+   Return the pointer to the state, if we found it in the DFA.
+   Otherwise create the new one and return it.  In case of an error
+   return NULL and set the error code in ERR.
+   Note: - We assume NULL as the invalid state, then it is possible that
+	   return value is NULL and ERR is REG_NOERROR.
+	 - We never return non-NULL value in case of any errors, it is for
+	   optimization.  */
+
+static re_dfastate_t *
+__attribute_warn_unused_result__
+re_acquire_state_context (reg_errcode_t *err, const re_dfa_t *dfa,
+			  const re_node_set *nodes, unsigned int context)
+{
+  re_hashval_t hash;
+  re_dfastate_t *new_state;
+  struct re_state_table_entry *spot;
+  Idx i;
+#if defined GCC_LINT || defined lint
+  /* Suppress bogus uninitialized-variable warnings.  */
+  *err = REG_NOERROR;
+#endif
+  if (nodes->nelem == 0)
+    {
+      *err = REG_NOERROR;
+      return NULL;
+    }
+  hash = calc_state_hash (nodes, context);
+  spot = dfa->state_table + (hash & dfa->state_hash_mask);
+
+  for (i = 0 ; i < spot->num ; i++)
+    {
+      re_dfastate_t *state = spot->array[i];
+      if (state->hash == hash
+	  && state->context == context
+	  && re_node_set_compare (state->entrance_nodes, nodes))
+	return state;
+    }
+  /* There are no appropriate state in 'dfa', create the new one.  */
+  new_state = create_cd_newstate (dfa, nodes, context, hash);
+  if (BE (new_state == NULL, 0))
+    *err = REG_ESPACE;
+
+  return new_state;
+}
+
+/* Finish initialization of the new state NEWSTATE, and using its hash value
+   HASH put in the appropriate bucket of DFA's state table.  Return value
+   indicates the error code if failed.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+register_state (const re_dfa_t *dfa, re_dfastate_t *newstate,
+		re_hashval_t hash)
+{
+  struct re_state_table_entry *spot;
+  reg_errcode_t err;
+  Idx i;
+
+  newstate->hash = hash;
+  err = re_node_set_alloc (&newstate->non_eps_nodes, newstate->nodes.nelem);
+  if (BE (err != REG_NOERROR, 0))
+    return REG_ESPACE;
+  for (i = 0; i < newstate->nodes.nelem; i++)
+    {
+      Idx elem = newstate->nodes.elems[i];
+      if (!IS_EPSILON_NODE (dfa->nodes[elem].type))
+	if (! re_node_set_insert_last (&newstate->non_eps_nodes, elem))
+	  return REG_ESPACE;
+    }
+
+  spot = dfa->state_table + (hash & dfa->state_hash_mask);
+  if (BE (spot->alloc <= spot->num, 0))
+    {
+      Idx new_alloc = 2 * spot->num + 2;
+      re_dfastate_t **new_array = re_realloc (spot->array, re_dfastate_t *,
+					      new_alloc);
+      if (BE (new_array == NULL, 0))
+	return REG_ESPACE;
+      spot->array = new_array;
+      spot->alloc = new_alloc;
+    }
+  spot->array[spot->num++] = newstate;
+  return REG_NOERROR;
+}
+
+static void
+free_state (re_dfastate_t *state)
+{
+  re_node_set_free (&state->non_eps_nodes);
+  re_node_set_free (&state->inveclosure);
+  if (state->entrance_nodes != &state->nodes)
+    {
+      re_node_set_free (state->entrance_nodes);
+      re_free (state->entrance_nodes);
+    }
+  re_node_set_free (&state->nodes);
+  re_free (state->word_trtable);
+  re_free (state->trtable);
+  re_free (state);
+}
+
+/* Create the new state which is independent of contexts.
+   Return the new state if succeeded, otherwise return NULL.  */
+
+static re_dfastate_t *
+__attribute_warn_unused_result__
+create_ci_newstate (const re_dfa_t *dfa, const re_node_set *nodes,
+		    re_hashval_t hash)
+{
+  Idx i;
+  reg_errcode_t err;
+  re_dfastate_t *newstate;
+
+  newstate = (re_dfastate_t *) calloc (sizeof (re_dfastate_t), 1);
+  if (BE (newstate == NULL, 0))
+    return NULL;
+  err = re_node_set_init_copy (&newstate->nodes, nodes);
+  if (BE (err != REG_NOERROR, 0))
+    {
+      re_free (newstate);
+      return NULL;
+    }
+
+  newstate->entrance_nodes = &newstate->nodes;
+  for (i = 0 ; i < nodes->nelem ; i++)
+    {
+      re_token_t *node = dfa->nodes + nodes->elems[i];
+      re_token_type_t type = node->type;
+      if (type == CHARACTER && !node->constraint)
+	continue;
+#ifdef RE_ENABLE_I18N
+      newstate->accept_mb |= node->accept_mb;
+#endif /* RE_ENABLE_I18N */
+
+      /* If the state has the halt node, the state is a halt state.  */
+      if (type == END_OF_RE)
+	newstate->halt = 1;
+      else if (type == OP_BACK_REF)
+	newstate->has_backref = 1;
+      else if (type == ANCHOR || node->constraint)
+	newstate->has_constraint = 1;
+    }
+  err = register_state (dfa, newstate, hash);
+  if (BE (err != REG_NOERROR, 0))
+    {
+      free_state (newstate);
+      newstate = NULL;
+    }
+  return newstate;
+}
+
+/* Create the new state which is depend on the context CONTEXT.
+   Return the new state if succeeded, otherwise return NULL.  */
+
+static re_dfastate_t *
+__attribute_warn_unused_result__
+create_cd_newstate (const re_dfa_t *dfa, const re_node_set *nodes,
+		    unsigned int context, re_hashval_t hash)
+{
+  Idx i, nctx_nodes = 0;
+  reg_errcode_t err;
+  re_dfastate_t *newstate;
+
+  newstate = (re_dfastate_t *) calloc (sizeof (re_dfastate_t), 1);
+  if (BE (newstate == NULL, 0))
+    return NULL;
+  err = re_node_set_init_copy (&newstate->nodes, nodes);
+  if (BE (err != REG_NOERROR, 0))
+    {
+      re_free (newstate);
+      return NULL;
+    }
+
+  newstate->context = context;
+  newstate->entrance_nodes = &newstate->nodes;
+
+  for (i = 0 ; i < nodes->nelem ; i++)
+    {
+      re_token_t *node = dfa->nodes + nodes->elems[i];
+      re_token_type_t type = node->type;
+      unsigned int constraint = node->constraint;
+
+      if (type == CHARACTER && !constraint)
+	continue;
+#ifdef RE_ENABLE_I18N
+      newstate->accept_mb |= node->accept_mb;
+#endif /* RE_ENABLE_I18N */
+
+      /* If the state has the halt node, the state is a halt state.  */
+      if (type == END_OF_RE)
+	newstate->halt = 1;
+      else if (type == OP_BACK_REF)
+	newstate->has_backref = 1;
+
+      if (constraint)
+	{
+	  if (newstate->entrance_nodes == &newstate->nodes)
+	    {
+	      newstate->entrance_nodes = re_malloc (re_node_set, 1);
+	      if (BE (newstate->entrance_nodes == NULL, 0))
+		{
+		  free_state (newstate);
+		  return NULL;
+		}
+	      if (re_node_set_init_copy (newstate->entrance_nodes, nodes)
+		  != REG_NOERROR)
+		return NULL;
+	      nctx_nodes = 0;
+	      newstate->has_constraint = 1;
+	    }
+
+	  if (NOT_SATISFY_PREV_CONSTRAINT (constraint,context))
+	    {
+	      re_node_set_remove_at (&newstate->nodes, i - nctx_nodes);
+	      ++nctx_nodes;
+	    }
+	}
+    }
+  err = register_state (dfa, newstate, hash);
+  if (BE (err != REG_NOERROR, 0))
+    {
+      free_state (newstate);
+      newstate = NULL;
+    }
+  return  newstate;
+}
diff --git a/lib/regex_internal.h b/lib/regex_internal.h
new file mode 100644
index 0000000000..7bbe802bc5
--- /dev/null
+++ b/lib/regex_internal.h
@@ -0,0 +1,911 @@
+/* Extended regular expression matching and search library.
+   Copyright (C) 2002-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Isamu Hasegawa <[email-masked]>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _REGEX_INTERNAL_H
+#define _REGEX_INTERNAL_H 1
+
+#include <assert.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <langinfo.h>
+#include <locale.h>
+#include <wchar.h>
+#include <wctype.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+/* Properties of integers.  Although Gnulib has intprops.h, glibc does
+   without for now.  */
+#ifndef _LIBC
+# include "intprops.h"
+#else
+/* True if the real type T is signed.  */
+# define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
+
+/* True if adding the nonnegative Idx values A and B would overflow.
+   If false, set *R to A + B.  A, B, and R may be evaluated more than
+   once, or zero times.  Although this is not a full implementation of
+   Gnulib INT_ADD_WRAPV, it is good enough for glibc regex code.
+   FIXME: This implementation is a fragile stopgap, and this file would
+   be simpler and more robust if intprops.h were migrated into glibc.  */
+# define INT_ADD_WRAPV(a, b, r) \
+   (IDX_MAX - (a) < (b) ? true : (*(r) = (a) + (b), false))
+#endif
+
+#ifdef _LIBC
+# include <libc-lock.h>
+# define lock_define(name) __libc_lock_define (, name)
+# define lock_init(lock) (__libc_lock_init (lock), 0)
+# define lock_fini(lock) ((void) 0)
+# define lock_lock(lock) __libc_lock_lock (lock)
+# define lock_unlock(lock) __libc_lock_unlock (lock)
+#elif defined GNULIB_LOCK && !defined USE_UNLOCKED_IO
+# include "glthread/lock.h"
+  /* Use gl_lock_define if empty macro arguments are known to work.
+     Otherwise, fall back on less-portable substitutes.  */
+# if ((defined __GNUC__ && !defined __STRICT_ANSI__) \
+      || (defined __STDC_VERSION__ && 199901L <= __STDC_VERSION__))
+#  define lock_define(name) gl_lock_define (, name)
+# elif USE_POSIX_THREADS
+#  define lock_define(name) pthread_mutex_t name;
+# elif USE_PTH_THREADS
+#  define lock_define(name) pth_mutex_t name;
+# elif USE_SOLARIS_THREADS
+#  define lock_define(name) mutex_t name;
+# elif USE_WINDOWS_THREADS
+#  define lock_define(name) gl_lock_t name;
+# else
+#  define lock_define(name)
+# endif
+# define lock_init(lock) glthread_lock_init (&(lock))
+# define lock_fini(lock) glthread_lock_destroy (&(lock))
+# define lock_lock(lock) glthread_lock_lock (&(lock))
+# define lock_unlock(lock) glthread_lock_unlock (&(lock))
+#elif defined GNULIB_PTHREAD && !defined USE_UNLOCKED_IO
+# include <pthread.h>
+# define lock_define(name) pthread_mutex_t name;
+# define lock_init(lock) pthread_mutex_init (&(lock), 0)
+# define lock_fini(lock) pthread_mutex_destroy (&(lock))
+# define lock_lock(lock) pthread_mutex_lock (&(lock))
+# define lock_unlock(lock) pthread_mutex_unlock (&(lock))
+#else
+# define lock_define(name)
+# define lock_init(lock) 0
+# define lock_fini(lock) ((void) 0)
+  /* The 'dfa' avoids an "unused variable 'dfa'" warning from GCC.  */
+# define lock_lock(lock) ((void) dfa)
+# define lock_unlock(lock) ((void) 0)
+#endif
+
+/* In case that the system doesn't have isblank().  */
+#if !defined _LIBC && ! (defined isblank || (HAVE_ISBLANK && HAVE_DECL_ISBLANK))
+# define isblank(ch) ((ch) == ' ' || (ch) == '\t')
+#endif
+
+#ifdef _LIBC
+# ifndef _RE_DEFINE_LOCALE_FUNCTIONS
+#  define _RE_DEFINE_LOCALE_FUNCTIONS 1
+#   include <locale/localeinfo.h>
+#   include <locale/coll-lookup.h>
+# endif
+#endif
+
+/* This is for other GNU distributions with internationalized messages.  */
+#if (HAVE_LIBINTL_H && ENABLE_NLS) || defined _LIBC
+# include <libintl.h>
+# ifdef _LIBC
+#  undef gettext
+#  define gettext(msgid) \
+  __dcgettext (_libc_intl_domainname, msgid, LC_MESSAGES)
+# endif
+#else
+# undef gettext
+# define gettext(msgid) (msgid)
+#endif
+
+#ifndef gettext_noop
+/* This define is so xgettext can find the internationalizable
+   strings.  */
+# define gettext_noop(String) String
+#endif
+
+#if (defined MB_CUR_MAX && HAVE_WCTYPE_H && HAVE_ISWCTYPE) || _LIBC
+# define RE_ENABLE_I18N
+#endif
+
+#define BE(expr, val) __builtin_expect (expr, val)
+
+/* Number of ASCII characters.  */
+#define ASCII_CHARS 0x80
+
+/* Number of single byte characters.  */
+#define SBC_MAX (UCHAR_MAX + 1)
+
+#define COLL_ELEM_LEN_MAX 8
+
+/* The character which represents newline.  */
+#define NEWLINE_CHAR '\n'
+#define WIDE_NEWLINE_CHAR L'\n'
+
+/* Rename to standard API for using out of glibc.  */
+#ifndef _LIBC
+# undef __wctype
+# undef __iswctype
+# define __wctype wctype
+# define __iswalnum iswalnum
+# define __iswctype iswctype
+# define __towlower towlower
+# define __towupper towupper
+# define __btowc btowc
+# define __mbrtowc mbrtowc
+# define __wcrtomb wcrtomb
+# define __regfree regfree
+# define attribute_hidden
+#endif /* not _LIBC */
+
+#if __GNUC__ < 3 + (__GNUC_MINOR__ < 1)
+# define __attribute__(arg)
+#endif
+
+#ifndef SSIZE_MAX
+# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
+#endif
+
+/* The type of indexes into strings.  This is signed, not size_t,
+   since the API requires indexes to fit in regoff_t anyway, and using
+   signed integers makes the code a bit smaller and presumably faster.
+   The traditional GNU regex implementation uses int for indexes.
+   The POSIX-compatible implementation uses a possibly-wider type.
+   The name 'Idx' is three letters to minimize the hassle of
+   reindenting a lot of regex code that formerly used 'int'.  */
+typedef regoff_t Idx;
+#ifdef _REGEX_LARGE_OFFSETS
+# define IDX_MAX SSIZE_MAX
+#else
+# define IDX_MAX INT_MAX
+#endif
+
+/* A hash value, suitable for computing hash tables.  */
+typedef __re_size_t re_hashval_t;
+
+/* An integer used to represent a set of bits.  It must be unsigned,
+   and must be at least as wide as unsigned int.  */
+typedef unsigned long int bitset_word_t;
+/* All bits set in a bitset_word_t.  */
+#define BITSET_WORD_MAX ULONG_MAX
+
+/* Number of bits in a bitset_word_t.  For portability to hosts with
+   padding bits, do not use '(sizeof (bitset_word_t) * CHAR_BIT)';
+   instead, deduce it directly from BITSET_WORD_MAX.  Avoid
+   greater-than-32-bit integers and unconditional shifts by more than
+   31 bits, as they're not portable.  */
+#if BITSET_WORD_MAX == 0xffffffffUL
+# define BITSET_WORD_BITS 32
+#elif BITSET_WORD_MAX >> 31 >> 4 == 1
+# define BITSET_WORD_BITS 36
+#elif BITSET_WORD_MAX >> 31 >> 16 == 1
+# define BITSET_WORD_BITS 48
+#elif BITSET_WORD_MAX >> 31 >> 28 == 1
+# define BITSET_WORD_BITS 60
+#elif BITSET_WORD_MAX >> 31 >> 31 >> 1 == 1
+# define BITSET_WORD_BITS 64
+#elif BITSET_WORD_MAX >> 31 >> 31 >> 9 == 1
+# define BITSET_WORD_BITS 72
+#elif BITSET_WORD_MAX >> 31 >> 31 >> 31 >> 31 >> 3 == 1
+# define BITSET_WORD_BITS 128
+#elif BITSET_WORD_MAX >> 31 >> 31 >> 31 >> 31 >> 31 >> 31 >> 31 >> 31 >> 7 == 1
+# define BITSET_WORD_BITS 256
+#elif BITSET_WORD_MAX >> 31 >> 31 >> 31 >> 31 >> 31 >> 31 >> 31 >> 31 >> 7 > 1
+# define BITSET_WORD_BITS 257 /* any value > SBC_MAX will do here */
+# if BITSET_WORD_BITS <= SBC_MAX
+#  error "Invalid SBC_MAX"
+# endif
+#else
+# error "Add case for new bitset_word_t size"
+#endif
+
+/* Number of bitset_word_t values in a bitset_t.  */
+#define BITSET_WORDS ((SBC_MAX + BITSET_WORD_BITS - 1) / BITSET_WORD_BITS)
+
+typedef bitset_word_t bitset_t[BITSET_WORDS];
+typedef bitset_word_t *re_bitset_ptr_t;
+typedef const bitset_word_t *re_const_bitset_ptr_t;
+
+#define PREV_WORD_CONSTRAINT 0x0001
+#define PREV_NOTWORD_CONSTRAINT 0x0002
+#define NEXT_WORD_CONSTRAINT 0x0004
+#define NEXT_NOTWORD_CONSTRAINT 0x0008
+#define PREV_NEWLINE_CONSTRAINT 0x0010
+#define NEXT_NEWLINE_CONSTRAINT 0x0020
+#define PREV_BEGBUF_CONSTRAINT 0x0040
+#define NEXT_ENDBUF_CONSTRAINT 0x0080
+#define WORD_DELIM_CONSTRAINT 0x0100
+#define NOT_WORD_DELIM_CONSTRAINT 0x0200
+
+typedef enum
+{
+  INSIDE_WORD = PREV_WORD_CONSTRAINT | NEXT_WORD_CONSTRAINT,
+  WORD_FIRST = PREV_NOTWORD_CONSTRAINT | NEXT_WORD_CONSTRAINT,
+  WORD_LAST = PREV_WORD_CONSTRAINT | NEXT_NOTWORD_CONSTRAINT,
+  INSIDE_NOTWORD = PREV_NOTWORD_CONSTRAINT | NEXT_NOTWORD_CONSTRAINT,
+  LINE_FIRST = PREV_NEWLINE_CONSTRAINT,
+  LINE_LAST = NEXT_NEWLINE_CONSTRAINT,
+  BUF_FIRST = PREV_BEGBUF_CONSTRAINT,
+  BUF_LAST = NEXT_ENDBUF_CONSTRAINT,
+  WORD_DELIM = WORD_DELIM_CONSTRAINT,
+  NOT_WORD_DELIM = NOT_WORD_DELIM_CONSTRAINT
+} re_context_type;
+
+typedef struct
+{
+  Idx alloc;
+  Idx nelem;
+  Idx *elems;
+} re_node_set;
+
+typedef enum
+{
+  NON_TYPE = 0,
+
+  /* Node type, These are used by token, node, tree.  */
+  CHARACTER = 1,
+  END_OF_RE = 2,
+  SIMPLE_BRACKET = 3,
+  OP_BACK_REF = 4,
+  OP_PERIOD = 5,
+#ifdef RE_ENABLE_I18N
+  COMPLEX_BRACKET = 6,
+  OP_UTF8_PERIOD = 7,
+#endif /* RE_ENABLE_I18N */
+
+  /* We define EPSILON_BIT as a macro so that OP_OPEN_SUBEXP is used
+     when the debugger shows values of this enum type.  */
+#define EPSILON_BIT 8
+  OP_OPEN_SUBEXP = EPSILON_BIT | 0,
+  OP_CLOSE_SUBEXP = EPSILON_BIT | 1,
+  OP_ALT = EPSILON_BIT | 2,
+  OP_DUP_ASTERISK = EPSILON_BIT | 3,
+  ANCHOR = EPSILON_BIT | 4,
+
+  /* Tree type, these are used only by tree. */
+  CONCAT = 16,
+  SUBEXP = 17,
+
+  /* Token type, these are used only by token.  */
+  OP_DUP_PLUS = 18,
+  OP_DUP_QUESTION,
+  OP_OPEN_BRACKET,
+  OP_CLOSE_BRACKET,
+  OP_CHARSET_RANGE,
+  OP_OPEN_DUP_NUM,
+  OP_CLOSE_DUP_NUM,
+  OP_NON_MATCH_LIST,
+  OP_OPEN_COLL_ELEM,
+  OP_CLOSE_COLL_ELEM,
+  OP_OPEN_EQUIV_CLASS,
+  OP_CLOSE_EQUIV_CLASS,
+  OP_OPEN_CHAR_CLASS,
+  OP_CLOSE_CHAR_CLASS,
+  OP_WORD,
+  OP_NOTWORD,
+  OP_SPACE,
+  OP_NOTSPACE,
+  BACK_SLASH
+
+} re_token_type_t;
+
+#ifdef RE_ENABLE_I18N
+typedef struct
+{
+  /* Multibyte characters.  */
+  wchar_t *mbchars;
+
+  /* Collating symbols.  */
+# ifdef _LIBC
+  int32_t *coll_syms;
+# endif
+
+  /* Equivalence classes. */
+# ifdef _LIBC
+  int32_t *equiv_classes;
+# endif
+
+  /* Range expressions. */
+# ifdef _LIBC
+  uint32_t *range_starts;
+  uint32_t *range_ends;
+# else /* not _LIBC */
+  wchar_t *range_starts;
+  wchar_t *range_ends;
+# endif /* not _LIBC */
+
+  /* Character classes. */
+  wctype_t *char_classes;
+
+  /* If this character set is the non-matching list.  */
+  unsigned int non_match : 1;
+
+  /* # of multibyte characters.  */
+  Idx nmbchars;
+
+  /* # of collating symbols.  */
+  Idx ncoll_syms;
+
+  /* # of equivalence classes. */
+  Idx nequiv_classes;
+
+  /* # of range expressions. */
+  Idx nranges;
+
+  /* # of character classes. */
+  Idx nchar_classes;
+} re_charset_t;
+#endif /* RE_ENABLE_I18N */
+
+typedef struct
+{
+  union
+  {
+    unsigned char c;		/* for CHARACTER */
+    re_bitset_ptr_t sbcset;	/* for SIMPLE_BRACKET */
+#ifdef RE_ENABLE_I18N
+    re_charset_t *mbcset;	/* for COMPLEX_BRACKET */
+#endif /* RE_ENABLE_I18N */
+    Idx idx;			/* for BACK_REF */
+    re_context_type ctx_type;	/* for ANCHOR */
+  } opr;
+#if __GNUC__ >= 2 && !defined __STRICT_ANSI__
+  re_token_type_t type : 8;
+#else
+  re_token_type_t type;
+#endif
+  unsigned int constraint : 10;	/* context constraint */
+  unsigned int duplicated : 1;
+  unsigned int opt_subexp : 1;
+#ifdef RE_ENABLE_I18N
+  unsigned int accept_mb : 1;
+  /* These 2 bits can be moved into the union if needed (e.g. if running out
+     of bits; move opr.c to opr.c.c and move the flags to opr.c.flags).  */
+  unsigned int mb_partial : 1;
+#endif
+  unsigned int word_char : 1;
+} re_token_t;
+
+#define IS_EPSILON_NODE(type) ((type) & EPSILON_BIT)
+
+struct re_string_t
+{
+  /* Indicate the raw buffer which is the original string passed as an
+     argument of regexec(), re_search(), etc..  */
+  const unsigned char *raw_mbs;
+  /* Store the multibyte string.  In case of "case insensitive mode" like
+     REG_ICASE, upper cases of the string are stored, otherwise MBS points
+     the same address that RAW_MBS points.  */
+  unsigned char *mbs;
+#ifdef RE_ENABLE_I18N
+  /* Store the wide character string which is corresponding to MBS.  */
+  wint_t *wcs;
+  Idx *offsets;
+  mbstate_t cur_state;
+#endif
+  /* Index in RAW_MBS.  Each character mbs[i] corresponds to
+     raw_mbs[raw_mbs_idx + i].  */
+  Idx raw_mbs_idx;
+  /* The length of the valid characters in the buffers.  */
+  Idx valid_len;
+  /* The corresponding number of bytes in raw_mbs array.  */
+  Idx valid_raw_len;
+  /* The length of the buffers MBS and WCS.  */
+  Idx bufs_len;
+  /* The index in MBS, which is updated by re_string_fetch_byte.  */
+  Idx cur_idx;
+  /* length of RAW_MBS array.  */
+  Idx raw_len;
+  /* This is RAW_LEN - RAW_MBS_IDX + VALID_LEN - VALID_RAW_LEN.  */
+  Idx len;
+  /* End of the buffer may be shorter than its length in the cases such
+     as re_match_2, re_search_2.  Then, we use STOP for end of the buffer
+     instead of LEN.  */
+  Idx raw_stop;
+  /* This is RAW_STOP - RAW_MBS_IDX adjusted through OFFSETS.  */
+  Idx stop;
+
+  /* The context of mbs[0].  We store the context independently, since
+     the context of mbs[0] may be different from raw_mbs[0], which is
+     the beginning of the input string.  */
+  unsigned int tip_context;
+  /* The translation passed as a part of an argument of re_compile_pattern.  */
+  RE_TRANSLATE_TYPE trans;
+  /* Copy of re_dfa_t's word_char.  */
+  re_const_bitset_ptr_t word_char;
+  /* true if REG_ICASE.  */
+  unsigned char icase;
+  unsigned char is_utf8;
+  unsigned char map_notascii;
+  unsigned char mbs_allocated;
+  unsigned char offsets_needed;
+  unsigned char newline_anchor;
+  unsigned char word_ops_used;
+  int mb_cur_max;
+};
+typedef struct re_string_t re_string_t;
+
+
+struct re_dfa_t;
+typedef struct re_dfa_t re_dfa_t;
+
+#ifndef _LIBC
+# define IS_IN(libc) false
+#endif
+
+#define re_string_peek_byte(pstr, offset) \
+  ((pstr)->mbs[(pstr)->cur_idx + offset])
+#define re_string_fetch_byte(pstr) \
+  ((pstr)->mbs[(pstr)->cur_idx++])
+#define re_string_first_byte(pstr, idx) \
+  ((idx) == (pstr)->valid_len || (pstr)->wcs[idx] != WEOF)
+#define re_string_is_single_byte_char(pstr, idx) \
+  ((pstr)->wcs[idx] != WEOF && ((pstr)->valid_len == (idx) + 1 \
+				|| (pstr)->wcs[(idx) + 1] != WEOF))
+#define re_string_eoi(pstr) ((pstr)->stop <= (pstr)->cur_idx)
+#define re_string_cur_idx(pstr) ((pstr)->cur_idx)
+#define re_string_get_buffer(pstr) ((pstr)->mbs)
+#define re_string_length(pstr) ((pstr)->len)
+#define re_string_byte_at(pstr,idx) ((pstr)->mbs[idx])
+#define re_string_skip_bytes(pstr,idx) ((pstr)->cur_idx += (idx))
+#define re_string_set_index(pstr,idx) ((pstr)->cur_idx = (idx))
+
+#if defined _LIBC || HAVE_ALLOCA
+# include <alloca.h>
+#endif
+
+#ifndef _LIBC
+# if HAVE_ALLOCA
+/* The OS usually guarantees only one guard page at the bottom of the stack,
+   and a page size can be as small as 4096 bytes.  So we cannot safely
+   allocate anything larger than 4096 bytes.  Also care for the possibility
+   of a few compiler-allocated temporary stack slots.  */
+#  define __libc_use_alloca(n) ((n) < 4032)
+# else
+/* alloca is implemented with malloc, so just use malloc.  */
+#  define __libc_use_alloca(n) 0
+#  undef alloca
+#  define alloca(n) malloc (n)
+# endif
+#endif
+
+#ifdef _LIBC
+# define MALLOC_0_IS_NONNULL 1
+#elif !defined MALLOC_0_IS_NONNULL
+# define MALLOC_0_IS_NONNULL 0
+#endif
+
+#ifndef MAX
+# define MAX(a,b) ((a) < (b) ? (b) : (a))
+#endif
+#ifndef MIN
+# define MIN(a,b) ((a) < (b) ? (a) : (b))
+#endif
+
+#define re_malloc(t,n) ((t *) malloc ((n) * sizeof (t)))
+#define re_realloc(p,t,n) ((t *) realloc (p, (n) * sizeof (t)))
+#define re_free(p) free (p)
+
+struct bin_tree_t
+{
+  struct bin_tree_t *parent;
+  struct bin_tree_t *left;
+  struct bin_tree_t *right;
+  struct bin_tree_t *first;
+  struct bin_tree_t *next;
+
+  re_token_t token;
+
+  /* 'node_idx' is the index in dfa->nodes, if 'type' == 0.
+     Otherwise 'type' indicate the type of this node.  */
+  Idx node_idx;
+};
+typedef struct bin_tree_t bin_tree_t;
+
+#define BIN_TREE_STORAGE_SIZE \
+  ((1024 - sizeof (void *)) / sizeof (bin_tree_t))
+
+struct bin_tree_storage_t
+{
+  struct bin_tree_storage_t *next;
+  bin_tree_t data[BIN_TREE_STORAGE_SIZE];
+};
+typedef struct bin_tree_storage_t bin_tree_storage_t;
+
+#define CONTEXT_WORD 1
+#define CONTEXT_NEWLINE (CONTEXT_WORD << 1)
+#define CONTEXT_BEGBUF (CONTEXT_NEWLINE << 1)
+#define CONTEXT_ENDBUF (CONTEXT_BEGBUF << 1)
+
+#define IS_WORD_CONTEXT(c) ((c) & CONTEXT_WORD)
+#define IS_NEWLINE_CONTEXT(c) ((c) & CONTEXT_NEWLINE)
+#define IS_BEGBUF_CONTEXT(c) ((c) & CONTEXT_BEGBUF)
+#define IS_ENDBUF_CONTEXT(c) ((c) & CONTEXT_ENDBUF)
+#define IS_ORDINARY_CONTEXT(c) ((c) == 0)
+
+#define IS_WORD_CHAR(ch) (isalnum (ch) || (ch) == '_')
+#define IS_NEWLINE(ch) ((ch) == NEWLINE_CHAR)
+#define IS_WIDE_WORD_CHAR(ch) (__iswalnum (ch) || (ch) == L'_')
+#define IS_WIDE_NEWLINE(ch) ((ch) == WIDE_NEWLINE_CHAR)
+
+#define NOT_SATISFY_PREV_CONSTRAINT(constraint,context) \
+ ((((constraint) & PREV_WORD_CONSTRAINT) && !IS_WORD_CONTEXT (context)) \
+  || ((constraint & PREV_NOTWORD_CONSTRAINT) && IS_WORD_CONTEXT (context)) \
+  || ((constraint & PREV_NEWLINE_CONSTRAINT) && !IS_NEWLINE_CONTEXT (context))\
+  || ((constraint & PREV_BEGBUF_CONSTRAINT) && !IS_BEGBUF_CONTEXT (context)))
+
+#define NOT_SATISFY_NEXT_CONSTRAINT(constraint,context) \
+ ((((constraint) & NEXT_WORD_CONSTRAINT) && !IS_WORD_CONTEXT (context)) \
+  || (((constraint) & NEXT_NOTWORD_CONSTRAINT) && IS_WORD_CONTEXT (context)) \
+  || (((constraint) & NEXT_NEWLINE_CONSTRAINT) && !IS_NEWLINE_CONTEXT (context)) \
+  || (((constraint) & NEXT_ENDBUF_CONSTRAINT) && !IS_ENDBUF_CONTEXT (context)))
+
+struct re_dfastate_t
+{
+  re_hashval_t hash;
+  re_node_set nodes;
+  re_node_set non_eps_nodes;
+  re_node_set inveclosure;
+  re_node_set *entrance_nodes;
+  struct re_dfastate_t **trtable, **word_trtable;
+  unsigned int context : 4;
+  unsigned int halt : 1;
+  /* If this state can accept "multi byte".
+     Note that we refer to multibyte characters, and multi character
+     collating elements as "multi byte".  */
+  unsigned int accept_mb : 1;
+  /* If this state has backreference node(s).  */
+  unsigned int has_backref : 1;
+  unsigned int has_constraint : 1;
+};
+typedef struct re_dfastate_t re_dfastate_t;
+
+struct re_state_table_entry
+{
+  Idx num;
+  Idx alloc;
+  re_dfastate_t **array;
+};
+
+/* Array type used in re_sub_match_last_t and re_sub_match_top_t.  */
+
+typedef struct
+{
+  Idx next_idx;
+  Idx alloc;
+  re_dfastate_t **array;
+} state_array_t;
+
+/* Store information about the node NODE whose type is OP_CLOSE_SUBEXP.  */
+
+typedef struct
+{
+  Idx node;
+  Idx str_idx; /* The position NODE match at.  */
+  state_array_t path;
+} re_sub_match_last_t;
+
+/* Store information about the node NODE whose type is OP_OPEN_SUBEXP.
+   And information about the node, whose type is OP_CLOSE_SUBEXP,
+   corresponding to NODE is stored in LASTS.  */
+
+typedef struct
+{
+  Idx str_idx;
+  Idx node;
+  state_array_t *path;
+  Idx alasts; /* Allocation size of LASTS.  */
+  Idx nlasts; /* The number of LASTS.  */
+  re_sub_match_last_t **lasts;
+} re_sub_match_top_t;
+
+struct re_backref_cache_entry
+{
+  Idx node;
+  Idx str_idx;
+  Idx subexp_from;
+  Idx subexp_to;
+  char more;
+  char unused;
+  unsigned short int eps_reachable_subexps_map;
+};
+
+typedef struct
+{
+  /* The string object corresponding to the input string.  */
+  re_string_t input;
+#if defined _LIBC || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L)
+  const re_dfa_t *const dfa;
+#else
+  const re_dfa_t *dfa;
+#endif
+  /* EFLAGS of the argument of regexec.  */
+  int eflags;
+  /* Where the matching ends.  */
+  Idx match_last;
+  Idx last_node;
+  /* The state log used by the matcher.  */
+  re_dfastate_t **state_log;
+  Idx state_log_top;
+  /* Back reference cache.  */
+  Idx nbkref_ents;
+  Idx abkref_ents;
+  struct re_backref_cache_entry *bkref_ents;
+  int max_mb_elem_len;
+  Idx nsub_tops;
+  Idx asub_tops;
+  re_sub_match_top_t **sub_tops;
+} re_match_context_t;
+
+typedef struct
+{
+  re_dfastate_t **sifted_states;
+  re_dfastate_t **limited_states;
+  Idx last_node;
+  Idx last_str_idx;
+  re_node_set limits;
+} re_sift_context_t;
+
+struct re_fail_stack_ent_t
+{
+  Idx idx;
+  Idx node;
+  regmatch_t *regs;
+  re_node_set eps_via_nodes;
+};
+
+struct re_fail_stack_t
+{
+  Idx num;
+  Idx alloc;
+  struct re_fail_stack_ent_t *stack;
+};
+
+struct re_dfa_t
+{
+  re_token_t *nodes;
+  size_t nodes_alloc;
+  size_t nodes_len;
+  Idx *nexts;
+  Idx *org_indices;
+  re_node_set *edests;
+  re_node_set *eclosures;
+  re_node_set *inveclosures;
+  struct re_state_table_entry *state_table;
+  re_dfastate_t *init_state;
+  re_dfastate_t *init_state_word;
+  re_dfastate_t *init_state_nl;
+  re_dfastate_t *init_state_begbuf;
+  bin_tree_t *str_tree;
+  bin_tree_storage_t *str_tree_storage;
+  re_bitset_ptr_t sb_char;
+  int str_tree_storage_idx;
+
+  /* number of subexpressions 're_nsub' is in regex_t.  */
+  re_hashval_t state_hash_mask;
+  Idx init_node;
+  Idx nbackref; /* The number of backreference in this dfa.  */
+
+  /* Bitmap expressing which backreference is used.  */
+  bitset_word_t used_bkref_map;
+  bitset_word_t completed_bkref_map;
+
+  unsigned int has_plural_match : 1;
+  /* If this dfa has "multibyte node", which is a backreference or
+     a node which can accept multibyte character or multi character
+     collating element.  */
+  unsigned int has_mb_node : 1;
+  unsigned int is_utf8 : 1;
+  unsigned int map_notascii : 1;
+  unsigned int word_ops_used : 1;
+  int mb_cur_max;
+  bitset_t word_char;
+  reg_syntax_t syntax;
+  Idx *subexp_map;
+#ifdef DEBUG
+  char* re_str;
+#endif
+  lock_define (lock)
+};
+
+#define re_node_set_init_empty(set) memset (set, '\0', sizeof (re_node_set))
+#define re_node_set_remove(set,id) \
+  (re_node_set_remove_at (set, re_node_set_contains (set, id) - 1))
+#define re_node_set_empty(p) ((p)->nelem = 0)
+#define re_node_set_free(set) re_free ((set)->elems)
+
+
+typedef enum
+{
+  SB_CHAR,
+  MB_CHAR,
+  EQUIV_CLASS,
+  COLL_SYM,
+  CHAR_CLASS
+} bracket_elem_type;
+
+typedef struct
+{
+  bracket_elem_type type;
+  union
+  {
+    unsigned char ch;
+    unsigned char *name;
+    wchar_t wch;
+  } opr;
+} bracket_elem_t;
+
+
+/* Functions for bitset_t operation.  */
+
+static inline void
+bitset_set (bitset_t set, Idx i)
+{
+  set[i / BITSET_WORD_BITS] |= (bitset_word_t) 1 << i % BITSET_WORD_BITS;
+}
+
+static inline void
+bitset_clear (bitset_t set, Idx i)
+{
+  set[i / BITSET_WORD_BITS] &= ~ ((bitset_word_t) 1 << i % BITSET_WORD_BITS);
+}
+
+static inline bool
+bitset_contain (const bitset_t set, Idx i)
+{
+  return (set[i / BITSET_WORD_BITS] >> i % BITSET_WORD_BITS) & 1;
+}
+
+static inline void
+bitset_empty (bitset_t set)
+{
+  memset (set, '\0', sizeof (bitset_t));
+}
+
+static inline void
+bitset_set_all (bitset_t set)
+{
+  memset (set, -1, sizeof (bitset_word_t) * (SBC_MAX / BITSET_WORD_BITS));
+  if (SBC_MAX % BITSET_WORD_BITS != 0)
+    set[BITSET_WORDS - 1] =
+      ((bitset_word_t) 1 << SBC_MAX % BITSET_WORD_BITS) - 1;
+}
+
+static inline void
+bitset_copy (bitset_t dest, const bitset_t src)
+{
+  memcpy (dest, src, sizeof (bitset_t));
+}
+
+static inline void
+bitset_not (bitset_t set)
+{
+  int bitset_i;
+  for (bitset_i = 0; bitset_i < SBC_MAX / BITSET_WORD_BITS; ++bitset_i)
+    set[bitset_i] = ~set[bitset_i];
+  if (SBC_MAX % BITSET_WORD_BITS != 0)
+    set[BITSET_WORDS - 1] =
+      ((((bitset_word_t) 1 << SBC_MAX % BITSET_WORD_BITS) - 1)
+       & ~set[BITSET_WORDS - 1]);
+}
+
+static inline void
+bitset_merge (bitset_t dest, const bitset_t src)
+{
+  int bitset_i;
+  for (bitset_i = 0; bitset_i < BITSET_WORDS; ++bitset_i)
+    dest[bitset_i] |= src[bitset_i];
+}
+
+static inline void
+bitset_mask (bitset_t dest, const bitset_t src)
+{
+  int bitset_i;
+  for (bitset_i = 0; bitset_i < BITSET_WORDS; ++bitset_i)
+    dest[bitset_i] &= src[bitset_i];
+}
+
+#ifdef RE_ENABLE_I18N
+/* Functions for re_string.  */
+static int
+__attribute__ ((pure, unused))
+re_string_char_size_at (const re_string_t *pstr, Idx idx)
+{
+  int byte_idx;
+  if (pstr->mb_cur_max == 1)
+    return 1;
+  for (byte_idx = 1; idx + byte_idx < pstr->valid_len; ++byte_idx)
+    if (pstr->wcs[idx + byte_idx] != WEOF)
+      break;
+  return byte_idx;
+}
+
+static wint_t
+__attribute__ ((pure, unused))
+re_string_wchar_at (const re_string_t *pstr, Idx idx)
+{
+  if (pstr->mb_cur_max == 1)
+    return (wint_t) pstr->mbs[idx];
+  return (wint_t) pstr->wcs[idx];
+}
+
+# ifdef _LIBC
+#  include <locale/weight.h>
+# endif
+
+static int
+__attribute__ ((pure, unused))
+re_string_elem_size_at (const re_string_t *pstr, Idx idx)
+{
+# ifdef _LIBC
+  const unsigned char *p, *extra;
+  const int32_t *table, *indirect;
+  uint_fast32_t nrules = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES);
+
+  if (nrules != 0)
+    {
+      table = (const int32_t *) _NL_CURRENT (LC_COLLATE, _NL_COLLATE_TABLEMB);
+      extra = (const unsigned char *)
+	_NL_CURRENT (LC_COLLATE, _NL_COLLATE_EXTRAMB);
+      indirect = (const int32_t *) _NL_CURRENT (LC_COLLATE,
+						_NL_COLLATE_INDIRECTMB);
+      p = pstr->mbs + idx;
+      findidx (table, indirect, extra, &p, pstr->len - idx);
+      return p - pstr->mbs - idx;
+    }
+  else
+# endif /* _LIBC */
+    return 1;
+}
+#endif /* RE_ENABLE_I18N */
+
+#ifndef __GNUC_PREREQ
+# if defined __GNUC__ && defined __GNUC_MINOR__
+#  define __GNUC_PREREQ(maj, min) \
+         ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
+# else
+#  define __GNUC_PREREQ(maj, min) 0
+# endif
+#endif
+
+#if __GNUC_PREREQ (3,4)
+# undef __attribute_warn_unused_result__
+# define __attribute_warn_unused_result__ \
+   __attribute__ ((__warn_unused_result__))
+#else
+# define __attribute_warn_unused_result__ /* empty */
+#endif
+
+#ifndef FALLTHROUGH
+# if __GNUC__ < 7
+#  define FALLTHROUGH ((void) 0)
+# else
+#  define FALLTHROUGH __attribute__ ((__fallthrough__))
+# endif
+#endif
+
+#endif /*  _REGEX_INTERNAL_H */
diff --git a/lib/regexec.c b/lib/regexec.c
new file mode 100644
index 0000000000..6591311164
--- /dev/null
+++ b/lib/regexec.c
@@ -0,0 +1,4324 @@
+/* Extended regular expression matching and search library.
+   Copyright (C) 2002-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Isamu Hasegawa <[email-masked]>.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+static reg_errcode_t match_ctx_init (re_match_context_t *cache, int eflags,
+				     Idx n);
+static void match_ctx_clean (re_match_context_t *mctx);
+static void match_ctx_free (re_match_context_t *cache);
+static reg_errcode_t match_ctx_add_entry (re_match_context_t *cache, Idx node,
+					  Idx str_idx, Idx from, Idx to);
+static Idx search_cur_bkref_entry (const re_match_context_t *mctx, Idx str_idx);
+static reg_errcode_t match_ctx_add_subtop (re_match_context_t *mctx, Idx node,
+					   Idx str_idx);
+static re_sub_match_last_t * match_ctx_add_sublast (re_sub_match_top_t *subtop,
+						    Idx node, Idx str_idx);
+static void sift_ctx_init (re_sift_context_t *sctx, re_dfastate_t **sifted_sts,
+			   re_dfastate_t **limited_sts, Idx last_node,
+			   Idx last_str_idx);
+static reg_errcode_t re_search_internal (const regex_t *preg,
+					 const char *string, Idx length,
+					 Idx start, Idx last_start, Idx stop,
+					 size_t nmatch, regmatch_t pmatch[],
+					 int eflags);
+static regoff_t re_search_2_stub (struct re_pattern_buffer *bufp,
+				  const char *string1, Idx length1,
+				  const char *string2, Idx length2,
+				  Idx start, regoff_t range,
+				  struct re_registers *regs,
+				  Idx stop, bool ret_len);
+static regoff_t re_search_stub (struct re_pattern_buffer *bufp,
+				const char *string, Idx length, Idx start,
+				regoff_t range, Idx stop,
+				struct re_registers *regs,
+				bool ret_len);
+static unsigned re_copy_regs (struct re_registers *regs, regmatch_t *pmatch,
+                              Idx nregs, int regs_allocated);
+static reg_errcode_t prune_impossible_nodes (re_match_context_t *mctx);
+static Idx check_matching (re_match_context_t *mctx, bool fl_longest_match,
+			   Idx *p_match_first);
+static Idx check_halt_state_context (const re_match_context_t *mctx,
+				     const re_dfastate_t *state, Idx idx);
+static void update_regs (const re_dfa_t *dfa, regmatch_t *pmatch,
+			 regmatch_t *prev_idx_match, Idx cur_node,
+			 Idx cur_idx, Idx nmatch);
+static reg_errcode_t push_fail_stack (struct re_fail_stack_t *fs,
+				      Idx str_idx, Idx dest_node, Idx nregs,
+				      regmatch_t *regs,
+				      re_node_set *eps_via_nodes);
+static reg_errcode_t set_regs (const regex_t *preg,
+			       const re_match_context_t *mctx,
+			       size_t nmatch, regmatch_t *pmatch,
+			       bool fl_backtrack);
+static reg_errcode_t free_fail_stack_return (struct re_fail_stack_t *fs);
+
+#ifdef RE_ENABLE_I18N
+static int sift_states_iter_mb (const re_match_context_t *mctx,
+				re_sift_context_t *sctx,
+				Idx node_idx, Idx str_idx, Idx max_str_idx);
+#endif /* RE_ENABLE_I18N */
+static reg_errcode_t sift_states_backward (const re_match_context_t *mctx,
+					   re_sift_context_t *sctx);
+static reg_errcode_t build_sifted_states (const re_match_context_t *mctx,
+					  re_sift_context_t *sctx, Idx str_idx,
+					  re_node_set *cur_dest);
+static reg_errcode_t update_cur_sifted_state (const re_match_context_t *mctx,
+					      re_sift_context_t *sctx,
+					      Idx str_idx,
+					      re_node_set *dest_nodes);
+static reg_errcode_t add_epsilon_src_nodes (const re_dfa_t *dfa,
+					    re_node_set *dest_nodes,
+					    const re_node_set *candidates);
+static bool check_dst_limits (const re_match_context_t *mctx,
+			      const re_node_set *limits,
+			      Idx dst_node, Idx dst_idx, Idx src_node,
+			      Idx src_idx);
+static int check_dst_limits_calc_pos_1 (const re_match_context_t *mctx,
+					int boundaries, Idx subexp_idx,
+					Idx from_node, Idx bkref_idx);
+static int check_dst_limits_calc_pos (const re_match_context_t *mctx,
+				      Idx limit, Idx subexp_idx,
+				      Idx node, Idx str_idx,
+				      Idx bkref_idx);
+static reg_errcode_t check_subexp_limits (const re_dfa_t *dfa,
+					  re_node_set *dest_nodes,
+					  const re_node_set *candidates,
+					  re_node_set *limits,
+					  struct re_backref_cache_entry *bkref_ents,
+					  Idx str_idx);
+static reg_errcode_t sift_states_bkref (const re_match_context_t *mctx,
+					re_sift_context_t *sctx,
+					Idx str_idx, const re_node_set *candidates);
+static reg_errcode_t merge_state_array (const re_dfa_t *dfa,
+					re_dfastate_t **dst,
+					re_dfastate_t **src, Idx num);
+static re_dfastate_t *find_recover_state (reg_errcode_t *err,
+					 re_match_context_t *mctx);
+static re_dfastate_t *transit_state (reg_errcode_t *err,
+				     re_match_context_t *mctx,
+				     re_dfastate_t *state);
+static re_dfastate_t *merge_state_with_log (reg_errcode_t *err,
+					    re_match_context_t *mctx,
+					    re_dfastate_t *next_state);
+static reg_errcode_t check_subexp_matching_top (re_match_context_t *mctx,
+						re_node_set *cur_nodes,
+						Idx str_idx);
+#if 0
+static re_dfastate_t *transit_state_sb (reg_errcode_t *err,
+					re_match_context_t *mctx,
+					re_dfastate_t *pstate);
+#endif
+#ifdef RE_ENABLE_I18N
+static reg_errcode_t transit_state_mb (re_match_context_t *mctx,
+				       re_dfastate_t *pstate);
+#endif /* RE_ENABLE_I18N */
+static reg_errcode_t transit_state_bkref (re_match_context_t *mctx,
+					  const re_node_set *nodes);
+static reg_errcode_t get_subexp (re_match_context_t *mctx,
+				 Idx bkref_node, Idx bkref_str_idx);
+static reg_errcode_t get_subexp_sub (re_match_context_t *mctx,
+				     const re_sub_match_top_t *sub_top,
+				     re_sub_match_last_t *sub_last,
+				     Idx bkref_node, Idx bkref_str);
+static Idx find_subexp_node (const re_dfa_t *dfa, const re_node_set *nodes,
+			     Idx subexp_idx, int type);
+static reg_errcode_t check_arrival (re_match_context_t *mctx,
+				    state_array_t *path, Idx top_node,
+				    Idx top_str, Idx last_node, Idx last_str,
+				    int type);
+static reg_errcode_t check_arrival_add_next_nodes (re_match_context_t *mctx,
+						   Idx str_idx,
+						   re_node_set *cur_nodes,
+						   re_node_set *next_nodes);
+static reg_errcode_t check_arrival_expand_ecl (const re_dfa_t *dfa,
+					       re_node_set *cur_nodes,
+					       Idx ex_subexp, int type);
+static reg_errcode_t check_arrival_expand_ecl_sub (const re_dfa_t *dfa,
+						   re_node_set *dst_nodes,
+						   Idx target, Idx ex_subexp,
+						   int type);
+static reg_errcode_t expand_bkref_cache (re_match_context_t *mctx,
+					 re_node_set *cur_nodes, Idx cur_str,
+					 Idx subexp_num, int type);
+static bool build_trtable (const re_dfa_t *dfa, re_dfastate_t *state);
+#ifdef RE_ENABLE_I18N
+static int check_node_accept_bytes (const re_dfa_t *dfa, Idx node_idx,
+				    const re_string_t *input, Idx idx);
+# ifdef _LIBC
+static unsigned int find_collation_sequence_value (const unsigned char *mbs,
+						   size_t name_len);
+# endif /* _LIBC */
+#endif /* RE_ENABLE_I18N */
+static Idx group_nodes_into_DFAstates (const re_dfa_t *dfa,
+				       const re_dfastate_t *state,
+				       re_node_set *states_node,
+				       bitset_t *states_ch);
+static bool check_node_accept (const re_match_context_t *mctx,
+			       const re_token_t *node, Idx idx);
+static reg_errcode_t extend_buffers (re_match_context_t *mctx, int min_len);
+
+/* Entry point for POSIX code.  */
+
+/* regexec searches for a given pattern, specified by PREG, in the
+   string STRING.
+
+   If NMATCH is zero or REG_NOSUB was set in the cflags argument to
+   'regcomp', we ignore PMATCH.  Otherwise, we assume PMATCH has at
+   least NMATCH elements, and we set them to the offsets of the
+   corresponding matched substrings.
+
+   EFLAGS specifies "execution flags" which affect matching: if
+   REG_NOTBOL is set, then ^ does not match at the beginning of the
+   string; if REG_NOTEOL is set, then $ does not match at the end.
+
+   We return 0 if we find a match and REG_NOMATCH if not.  */
+
+int
+regexec (const regex_t *_Restrict_ preg, const char *_Restrict_ string,
+	 size_t nmatch, regmatch_t pmatch[], int eflags)
+{
+  reg_errcode_t err;
+  Idx start, length;
+  re_dfa_t *dfa = preg->buffer;
+
+  if (eflags & ~(REG_NOTBOL | REG_NOTEOL | REG_STARTEND))
+    return REG_BADPAT;
+
+  if (eflags & REG_STARTEND)
+    {
+      start = pmatch[0].rm_so;
+      length = pmatch[0].rm_eo;
+    }
+  else
+    {
+      start = 0;
+      length = strlen (string);
+    }
+
+  lock_lock (dfa->lock);
+  if (preg->no_sub)
+    err = re_search_internal (preg, string, length, start, length,
+			      length, 0, NULL, eflags);
+  else
+    err = re_search_internal (preg, string, length, start, length,
+			      length, nmatch, pmatch, eflags);
+  lock_unlock (dfa->lock);
+  return err != REG_NOERROR;
+}
+
+#ifdef _LIBC
+libc_hidden_def (__regexec)
+
+# include <shlib-compat.h>
+versioned_symbol (libc, __regexec, regexec, GLIBC_2_3_4);
+
+# if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_3_4)
+__typeof__ (__regexec) __compat_regexec;
+
+int
+attribute_compat_text_section
+__compat_regexec (const regex_t *_Restrict_ preg,
+		  const char *_Restrict_ string, size_t nmatch,
+		  regmatch_t pmatch[], int eflags)
+{
+  return regexec (preg, string, nmatch, pmatch,
+		  eflags & (REG_NOTBOL | REG_NOTEOL));
+}
+compat_symbol (libc, __compat_regexec, regexec, GLIBC_2_0);
+# endif
+#endif
+
+/* Entry points for GNU code.  */
+
+/* re_match, re_search, re_match_2, re_search_2
+
+   The former two functions operate on STRING with length LENGTH,
+   while the later two operate on concatenation of STRING1 and STRING2
+   with lengths LENGTH1 and LENGTH2, respectively.
+
+   re_match() matches the compiled pattern in BUFP against the string,
+   starting at index START.
+
+   re_search() first tries matching at index START, then it tries to match
+   starting from index START + 1, and so on.  The last start position tried
+   is START + RANGE.  (Thus RANGE = 0 forces re_search to operate the same
+   way as re_match().)
+
+   The parameter STOP of re_{match,search}_2 specifies that no match exceeding
+   the first STOP characters of the concatenation of the strings should be
+   concerned.
+
+   If REGS is not NULL, and BUFP->no_sub is not set, the offsets of the match
+   and all groups is stored in REGS.  (For the "_2" variants, the offsets are
+   computed relative to the concatenation, not relative to the individual
+   strings.)
+
+   On success, re_match* functions return the length of the match, re_search*
+   return the position of the start of the match.  Return value -1 means no
+   match was found and -2 indicates an internal error.  */
+
+regoff_t
+re_match (struct re_pattern_buffer *bufp, const char *string, Idx length,
+	  Idx start, struct re_registers *regs)
+{
+  return re_search_stub (bufp, string, length, start, 0, length, regs, true);
+}
+#ifdef _LIBC
+weak_alias (__re_match, re_match)
+#endif
+
+regoff_t
+re_search (struct re_pattern_buffer *bufp, const char *string, Idx length,
+	   Idx start, regoff_t range, struct re_registers *regs)
+{
+  return re_search_stub (bufp, string, length, start, range, length, regs,
+			 false);
+}
+#ifdef _LIBC
+weak_alias (__re_search, re_search)
+#endif
+
+regoff_t
+re_match_2 (struct re_pattern_buffer *bufp, const char *string1, Idx length1,
+	    const char *string2, Idx length2, Idx start,
+	    struct re_registers *regs, Idx stop)
+{
+  return re_search_2_stub (bufp, string1, length1, string2, length2,
+			   start, 0, regs, stop, true);
+}
+#ifdef _LIBC
+weak_alias (__re_match_2, re_match_2)
+#endif
+
+regoff_t
+re_search_2 (struct re_pattern_buffer *bufp, const char *string1, Idx length1,
+	     const char *string2, Idx length2, Idx start, regoff_t range,
+	     struct re_registers *regs, Idx stop)
+{
+  return re_search_2_stub (bufp, string1, length1, string2, length2,
+			   start, range, regs, stop, false);
+}
+#ifdef _LIBC
+weak_alias (__re_search_2, re_search_2)
+#endif
+
+static regoff_t
+re_search_2_stub (struct re_pattern_buffer *bufp, const char *string1,
+		  Idx length1, const char *string2, Idx length2, Idx start,
+		  regoff_t range, struct re_registers *regs,
+		  Idx stop, bool ret_len)
+{
+  const char *str;
+  regoff_t rval;
+  Idx len;
+  char *s = NULL;
+
+  if (BE ((length1 < 0 || length2 < 0 || stop < 0
+           || INT_ADD_WRAPV (length1, length2, &len)),
+          0))
+    return -2;
+
+  /* Concatenate the strings.  */
+  if (length2 > 0)
+    if (length1 > 0)
+      {
+	s = re_malloc (char, len);
+
+	if (BE (s == NULL, 0))
+	  return -2;
+#ifdef _LIBC
+	memcpy (__mempcpy (s, string1, length1), string2, length2);
+#else
+	memcpy (s, string1, length1);
+	memcpy (s + length1, string2, length2);
+#endif
+	str = s;
+      }
+    else
+      str = string2;
+  else
+    str = string1;
+
+  rval = re_search_stub (bufp, str, len, start, range, stop, regs,
+			 ret_len);
+  re_free (s);
+  return rval;
+}
+
+/* The parameters have the same meaning as those of re_search.
+   Additional parameters:
+   If RET_LEN is true the length of the match is returned (re_match style);
+   otherwise the position of the match is returned.  */
+
+static regoff_t
+re_search_stub (struct re_pattern_buffer *bufp, const char *string, Idx length,
+		Idx start, regoff_t range, Idx stop, struct re_registers *regs,
+		bool ret_len)
+{
+  reg_errcode_t result;
+  regmatch_t *pmatch;
+  Idx nregs;
+  regoff_t rval;
+  int eflags = 0;
+  re_dfa_t *dfa = bufp->buffer;
+  Idx last_start = start + range;
+
+  /* Check for out-of-range.  */
+  if (BE (start < 0 || start > length, 0))
+    return -1;
+  if (BE (length < last_start || (0 <= range && last_start < start), 0))
+    last_start = length;
+  else if (BE (last_start < 0 || (range < 0 && start <= last_start), 0))
+    last_start = 0;
+
+  lock_lock (dfa->lock);
+
+  eflags |= (bufp->not_bol) ? REG_NOTBOL : 0;
+  eflags |= (bufp->not_eol) ? REG_NOTEOL : 0;
+
+  /* Compile fastmap if we haven't yet.  */
+  if (start < last_start && bufp->fastmap != NULL && !bufp->fastmap_accurate)
+    re_compile_fastmap (bufp);
+
+  if (BE (bufp->no_sub, 0))
+    regs = NULL;
+
+  /* We need at least 1 register.  */
+  if (regs == NULL)
+    nregs = 1;
+  else if (BE (bufp->regs_allocated == REGS_FIXED
+	       && regs->num_regs <= bufp->re_nsub, 0))
+    {
+      nregs = regs->num_regs;
+      if (BE (nregs < 1, 0))
+	{
+	  /* Nothing can be copied to regs.  */
+	  regs = NULL;
+	  nregs = 1;
+	}
+    }
+  else
+    nregs = bufp->re_nsub + 1;
+  pmatch = re_malloc (regmatch_t, nregs);
+  if (BE (pmatch == NULL, 0))
+    {
+      rval = -2;
+      goto out;
+    }
+
+  result = re_search_internal (bufp, string, length, start, last_start, stop,
+			       nregs, pmatch, eflags);
+
+  rval = 0;
+
+  /* I hope we needn't fill their regs with -1's when no match was found.  */
+  if (result != REG_NOERROR)
+    rval = result == REG_NOMATCH ? -1 : -2;
+  else if (regs != NULL)
+    {
+      /* If caller wants register contents data back, copy them.  */
+      bufp->regs_allocated = re_copy_regs (regs, pmatch, nregs,
+					   bufp->regs_allocated);
+      if (BE (bufp->regs_allocated == REGS_UNALLOCATED, 0))
+	rval = -2;
+    }
+
+  if (BE (rval == 0, 1))
+    {
+      if (ret_len)
+	{
+	  assert (pmatch[0].rm_so == start);
+	  rval = pmatch[0].rm_eo - start;
+	}
+      else
+	rval = pmatch[0].rm_so;
+    }
+  re_free (pmatch);
+ out:
+  lock_unlock (dfa->lock);
+  return rval;
+}
+
+static unsigned
+re_copy_regs (struct re_registers *regs, regmatch_t *pmatch, Idx nregs,
+	      int regs_allocated)
+{
+  int rval = REGS_REALLOCATE;
+  Idx i;
+  Idx need_regs = nregs + 1;
+  /* We need one extra element beyond 'num_regs' for the '-1' marker GNU code
+     uses.  */
+
+  /* Have the register data arrays been allocated?  */
+  if (regs_allocated == REGS_UNALLOCATED)
+    { /* No.  So allocate them with malloc.  */
+      regs->start = re_malloc (regoff_t, need_regs);
+      if (BE (regs->start == NULL, 0))
+	return REGS_UNALLOCATED;
+      regs->end = re_malloc (regoff_t, need_regs);
+      if (BE (regs->end == NULL, 0))
+	{
+	  re_free (regs->start);
+	  return REGS_UNALLOCATED;
+	}
+      regs->num_regs = need_regs;
+    }
+  else if (regs_allocated == REGS_REALLOCATE)
+    { /* Yes.  If we need more elements than were already
+	 allocated, reallocate them.  If we need fewer, just
+	 leave it alone.  */
+      if (BE (need_regs > regs->num_regs, 0))
+	{
+	  regoff_t *new_start = re_realloc (regs->start, regoff_t, need_regs);
+	  regoff_t *new_end;
+	  if (BE (new_start == NULL, 0))
+	    return REGS_UNALLOCATED;
+	  new_end = re_realloc (regs->end, regoff_t, need_regs);
+	  if (BE (new_end == NULL, 0))
+	    {
+	      re_free (new_start);
+	      return REGS_UNALLOCATED;
+	    }
+	  regs->start = new_start;
+	  regs->end = new_end;
+	  regs->num_regs = need_regs;
+	}
+    }
+  else
+    {
+      assert (regs_allocated == REGS_FIXED);
+      /* This function may not be called with REGS_FIXED and nregs too big.  */
+      assert (regs->num_regs >= nregs);
+      rval = REGS_FIXED;
+    }
+
+  /* Copy the regs.  */
+  for (i = 0; i < nregs; ++i)
+    {
+      regs->start[i] = pmatch[i].rm_so;
+      regs->end[i] = pmatch[i].rm_eo;
+    }
+  for ( ; i < regs->num_regs; ++i)
+    regs->start[i] = regs->end[i] = -1;
+
+  return rval;
+}
+
+/* Set REGS to hold NUM_REGS registers, storing them in STARTS and
+   ENDS.  Subsequent matches using PATTERN_BUFFER and REGS will use
+   this memory for recording register information.  STARTS and ENDS
+   must be allocated using the malloc library routine, and must each
+   be at least NUM_REGS * sizeof (regoff_t) bytes long.
+
+   If NUM_REGS == 0, then subsequent matches should allocate their own
+   register data.
+
+   Unless this function is called, the first search or match using
+   PATTERN_BUFFER will allocate its own register data, without
+   freeing the old data.  */
+
+void
+re_set_registers (struct re_pattern_buffer *bufp, struct re_registers *regs,
+		  __re_size_t num_regs, regoff_t *starts, regoff_t *ends)
+{
+  if (num_regs)
+    {
+      bufp->regs_allocated = REGS_REALLOCATE;
+      regs->num_regs = num_regs;
+      regs->start = starts;
+      regs->end = ends;
+    }
+  else
+    {
+      bufp->regs_allocated = REGS_UNALLOCATED;
+      regs->num_regs = 0;
+      regs->start = regs->end = NULL;
+    }
+}
+#ifdef _LIBC
+weak_alias (__re_set_registers, re_set_registers)
+#endif
+
+/* Entry points compatible with 4.2 BSD regex library.  We don't define
+   them unless specifically requested.  */
+
+#if defined _REGEX_RE_COMP || defined _LIBC
+int
+# ifdef _LIBC
+weak_function
+# endif
+re_exec (const char *s)
+{
+  return 0 == regexec (&re_comp_buf, s, 0, NULL, 0);
+}
+#endif /* _REGEX_RE_COMP */
+
+/* Internal entry point.  */
+
+/* Searches for a compiled pattern PREG in the string STRING, whose
+   length is LENGTH.  NMATCH, PMATCH, and EFLAGS have the same
+   meaning as with regexec.  LAST_START is START + RANGE, where
+   START and RANGE have the same meaning as with re_search.
+   Return REG_NOERROR if we find a match, and REG_NOMATCH if not,
+   otherwise return the error code.
+   Note: We assume front end functions already check ranges.
+   (0 <= LAST_START && LAST_START <= LENGTH)  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+re_search_internal (const regex_t *preg, const char *string, Idx length,
+		    Idx start, Idx last_start, Idx stop, size_t nmatch,
+		    regmatch_t pmatch[], int eflags)
+{
+  reg_errcode_t err;
+  const re_dfa_t *dfa = preg->buffer;
+  Idx left_lim, right_lim;
+  int incr;
+  bool fl_longest_match;
+  int match_kind;
+  Idx match_first;
+  Idx match_last = -1;
+  Idx extra_nmatch;
+  bool sb;
+  int ch;
+#if defined _LIBC || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L)
+  re_match_context_t mctx = { .dfa = dfa };
+#else
+  re_match_context_t mctx;
+#endif
+  char *fastmap = ((preg->fastmap != NULL && preg->fastmap_accurate
+		    && start != last_start && !preg->can_be_null)
+		   ? preg->fastmap : NULL);
+  RE_TRANSLATE_TYPE t = preg->translate;
+
+#if !(defined _LIBC || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
+  memset (&mctx, '\0', sizeof (re_match_context_t));
+  mctx.dfa = dfa;
+#endif
+
+  extra_nmatch = (nmatch > preg->re_nsub) ? nmatch - (preg->re_nsub + 1) : 0;
+  nmatch -= extra_nmatch;
+
+  /* Check if the DFA haven't been compiled.  */
+  if (BE (preg->used == 0 || dfa->init_state == NULL
+	  || dfa->init_state_word == NULL || dfa->init_state_nl == NULL
+	  || dfa->init_state_begbuf == NULL, 0))
+    return REG_NOMATCH;
+
+#ifdef DEBUG
+  /* We assume front-end functions already check them.  */
+  assert (0 <= last_start && last_start <= length);
+#endif
+
+  /* If initial states with non-begbuf contexts have no elements,
+     the regex must be anchored.  If preg->newline_anchor is set,
+     we'll never use init_state_nl, so do not check it.  */
+  if (dfa->init_state->nodes.nelem == 0
+      && dfa->init_state_word->nodes.nelem == 0
+      && (dfa->init_state_nl->nodes.nelem == 0
+	  || !preg->newline_anchor))
+    {
+      if (start != 0 && last_start != 0)
+        return REG_NOMATCH;
+      start = last_start = 0;
+    }
+
+  /* We must check the longest matching, if nmatch > 0.  */
+  fl_longest_match = (nmatch != 0 || dfa->nbackref);
+
+  err = re_string_allocate (&mctx.input, string, length, dfa->nodes_len + 1,
+			    preg->translate, (preg->syntax & RE_ICASE) != 0,
+			    dfa);
+  if (BE (err != REG_NOERROR, 0))
+    goto free_return;
+  mctx.input.stop = stop;
+  mctx.input.raw_stop = stop;
+  mctx.input.newline_anchor = preg->newline_anchor;
+
+  err = match_ctx_init (&mctx, eflags, dfa->nbackref * 2);
+  if (BE (err != REG_NOERROR, 0))
+    goto free_return;
+
+  /* We will log all the DFA states through which the dfa pass,
+     if nmatch > 1, or this dfa has "multibyte node", which is a
+     back-reference or a node which can accept multibyte character or
+     multi character collating element.  */
+  if (nmatch > 1 || dfa->has_mb_node)
+    {
+      /* Avoid overflow.  */
+      if (BE ((MIN (IDX_MAX, SIZE_MAX / sizeof (re_dfastate_t *))
+               <= mctx.input.bufs_len), 0))
+	{
+	  err = REG_ESPACE;
+	  goto free_return;
+	}
+
+      mctx.state_log = re_malloc (re_dfastate_t *, mctx.input.bufs_len + 1);
+      if (BE (mctx.state_log == NULL, 0))
+	{
+	  err = REG_ESPACE;
+	  goto free_return;
+	}
+    }
+  else
+    mctx.state_log = NULL;
+
+  match_first = start;
+  mctx.input.tip_context = (eflags & REG_NOTBOL) ? CONTEXT_BEGBUF
+			   : CONTEXT_NEWLINE | CONTEXT_BEGBUF;
+
+  /* Check incrementally whether the input string matches.  */
+  incr = (last_start < start) ? -1 : 1;
+  left_lim = (last_start < start) ? last_start : start;
+  right_lim = (last_start < start) ? start : last_start;
+  sb = dfa->mb_cur_max == 1;
+  match_kind =
+    (fastmap
+     ? ((sb || !(preg->syntax & RE_ICASE || t) ? 4 : 0)
+	| (start <= last_start ? 2 : 0)
+	| (t != NULL ? 1 : 0))
+     : 8);
+
+  for (;; match_first += incr)
+    {
+      err = REG_NOMATCH;
+      if (match_first < left_lim || right_lim < match_first)
+	goto free_return;
+
+      /* Advance as rapidly as possible through the string, until we
+	 find a plausible place to start matching.  This may be done
+	 with varying efficiency, so there are various possibilities:
+	 only the most common of them are specialized, in order to
+	 save on code size.  We use a switch statement for speed.  */
+      switch (match_kind)
+	{
+	case 8:
+	  /* No fastmap.  */
+	  break;
+
+	case 7:
+	  /* Fastmap with single-byte translation, match forward.  */
+	  while (BE (match_first < right_lim, 1)
+		 && !fastmap[t[(unsigned char) string[match_first]]])
+	    ++match_first;
+	  goto forward_match_found_start_or_reached_end;
+
+	case 6:
+	  /* Fastmap without translation, match forward.  */
+	  while (BE (match_first < right_lim, 1)
+		 && !fastmap[(unsigned char) string[match_first]])
+	    ++match_first;
+
+	forward_match_found_start_or_reached_end:
+	  if (BE (match_first == right_lim, 0))
+	    {
+	      ch = match_first >= length
+		       ? 0 : (unsigned char) string[match_first];
+	      if (!fastmap[t ? t[ch] : ch])
+		goto free_return;
+	    }
+	  break;
+
+	case 4:
+	case 5:
+	  /* Fastmap without multi-byte translation, match backwards.  */
+	  while (match_first >= left_lim)
+	    {
+	      ch = match_first >= length
+		       ? 0 : (unsigned char) string[match_first];
+	      if (fastmap[t ? t[ch] : ch])
+		break;
+	      --match_first;
+	    }
+	  if (match_first < left_lim)
+	    goto free_return;
+	  break;
+
+	default:
+	  /* In this case, we can't determine easily the current byte,
+	     since it might be a component byte of a multibyte
+	     character.  Then we use the constructed buffer instead.  */
+	  for (;;)
+	    {
+	      /* If MATCH_FIRST is out of the valid range, reconstruct the
+		 buffers.  */
+	      __re_size_t offset = match_first - mctx.input.raw_mbs_idx;
+	      if (BE (offset >= (__re_size_t) mctx.input.valid_raw_len, 0))
+		{
+		  err = re_string_reconstruct (&mctx.input, match_first,
+					       eflags);
+		  if (BE (err != REG_NOERROR, 0))
+		    goto free_return;
+
+		  offset = match_first - mctx.input.raw_mbs_idx;
+		}
+	      /* If MATCH_FIRST is out of the buffer, leave it as '\0'.
+		 Note that MATCH_FIRST must not be smaller than 0.  */
+	      ch = (match_first >= length
+		    ? 0 : re_string_byte_at (&mctx.input, offset));
+	      if (fastmap[ch])
+		break;
+	      match_first += incr;
+	      if (match_first < left_lim || match_first > right_lim)
+		{
+		  err = REG_NOMATCH;
+		  goto free_return;
+		}
+	    }
+	  break;
+	}
+
+      /* Reconstruct the buffers so that the matcher can assume that
+	 the matching starts from the beginning of the buffer.  */
+      err = re_string_reconstruct (&mctx.input, match_first, eflags);
+      if (BE (err != REG_NOERROR, 0))
+	goto free_return;
+
+#ifdef RE_ENABLE_I18N
+     /* Don't consider this char as a possible match start if it part,
+	yet isn't the head, of a multibyte character.  */
+      if (!sb && !re_string_first_byte (&mctx.input, 0))
+	continue;
+#endif
+
+      /* It seems to be appropriate one, then use the matcher.  */
+      /* We assume that the matching starts from 0.  */
+      mctx.state_log_top = mctx.nbkref_ents = mctx.max_mb_elem_len = 0;
+      match_last = check_matching (&mctx, fl_longest_match,
+				   start <= last_start ? &match_first : NULL);
+      if (match_last != -1)
+	{
+	  if (BE (match_last == -2, 0))
+	    {
+	      err = REG_ESPACE;
+	      goto free_return;
+	    }
+	  else
+	    {
+	      mctx.match_last = match_last;
+	      if ((!preg->no_sub && nmatch > 1) || dfa->nbackref)
+		{
+		  re_dfastate_t *pstate = mctx.state_log[match_last];
+		  mctx.last_node = check_halt_state_context (&mctx, pstate,
+							     match_last);
+		}
+	      if ((!preg->no_sub && nmatch > 1 && dfa->has_plural_match)
+		  || dfa->nbackref)
+		{
+		  err = prune_impossible_nodes (&mctx);
+		  if (err == REG_NOERROR)
+		    break;
+		  if (BE (err != REG_NOMATCH, 0))
+		    goto free_return;
+		  match_last = -1;
+		}
+	      else
+		break; /* We found a match.  */
+	    }
+	}
+
+      match_ctx_clean (&mctx);
+    }
+
+#ifdef DEBUG
+  assert (match_last != -1);
+  assert (err == REG_NOERROR);
+#endif
+
+  /* Set pmatch[] if we need.  */
+  if (nmatch > 0)
+    {
+      Idx reg_idx;
+
+      /* Initialize registers.  */
+      for (reg_idx = 1; reg_idx < nmatch; ++reg_idx)
+	pmatch[reg_idx].rm_so = pmatch[reg_idx].rm_eo = -1;
+
+      /* Set the points where matching start/end.  */
+      pmatch[0].rm_so = 0;
+      pmatch[0].rm_eo = mctx.match_last;
+      /* FIXME: This function should fail if mctx.match_last exceeds
+	 the maximum possible regoff_t value.  We need a new error
+	 code REG_OVERFLOW.  */
+
+      if (!preg->no_sub && nmatch > 1)
+	{
+	  err = set_regs (preg, &mctx, nmatch, pmatch,
+			  dfa->has_plural_match && dfa->nbackref > 0);
+	  if (BE (err != REG_NOERROR, 0))
+	    goto free_return;
+	}
+
+      /* At last, add the offset to each register, since we slid
+	 the buffers so that we could assume that the matching starts
+	 from 0.  */
+      for (reg_idx = 0; reg_idx < nmatch; ++reg_idx)
+	if (pmatch[reg_idx].rm_so != -1)
+	  {
+#ifdef RE_ENABLE_I18N
+	    if (BE (mctx.input.offsets_needed != 0, 0))
+	      {
+		pmatch[reg_idx].rm_so =
+		  (pmatch[reg_idx].rm_so == mctx.input.valid_len
+		   ? mctx.input.valid_raw_len
+		   : mctx.input.offsets[pmatch[reg_idx].rm_so]);
+		pmatch[reg_idx].rm_eo =
+		  (pmatch[reg_idx].rm_eo == mctx.input.valid_len
+		   ? mctx.input.valid_raw_len
+		   : mctx.input.offsets[pmatch[reg_idx].rm_eo]);
+	      }
+#else
+	    assert (mctx.input.offsets_needed == 0);
+#endif
+	    pmatch[reg_idx].rm_so += match_first;
+	    pmatch[reg_idx].rm_eo += match_first;
+	  }
+      for (reg_idx = 0; reg_idx < extra_nmatch; ++reg_idx)
+	{
+	  pmatch[nmatch + reg_idx].rm_so = -1;
+	  pmatch[nmatch + reg_idx].rm_eo = -1;
+	}
+
+      if (dfa->subexp_map)
+	for (reg_idx = 0; reg_idx + 1 < nmatch; reg_idx++)
+	  if (dfa->subexp_map[reg_idx] != reg_idx)
+	    {
+	      pmatch[reg_idx + 1].rm_so
+		= pmatch[dfa->subexp_map[reg_idx] + 1].rm_so;
+	      pmatch[reg_idx + 1].rm_eo
+		= pmatch[dfa->subexp_map[reg_idx] + 1].rm_eo;
+	    }
+    }
+
+ free_return:
+  re_free (mctx.state_log);
+  if (dfa->nbackref)
+    match_ctx_free (&mctx);
+  re_string_destruct (&mctx.input);
+  return err;
+}
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+prune_impossible_nodes (re_match_context_t *mctx)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  Idx halt_node, match_last;
+  reg_errcode_t ret;
+  re_dfastate_t **sifted_states;
+  re_dfastate_t **lim_states = NULL;
+  re_sift_context_t sctx;
+#ifdef DEBUG
+  assert (mctx->state_log != NULL);
+#endif
+  match_last = mctx->match_last;
+  halt_node = mctx->last_node;
+
+  /* Avoid overflow.  */
+  if (BE (MIN (IDX_MAX, SIZE_MAX / sizeof (re_dfastate_t *)) <= match_last, 0))
+    return REG_ESPACE;
+
+  sifted_states = re_malloc (re_dfastate_t *, match_last + 1);
+  if (BE (sifted_states == NULL, 0))
+    {
+      ret = REG_ESPACE;
+      goto free_return;
+    }
+  if (dfa->nbackref)
+    {
+      lim_states = re_malloc (re_dfastate_t *, match_last + 1);
+      if (BE (lim_states == NULL, 0))
+	{
+	  ret = REG_ESPACE;
+	  goto free_return;
+	}
+      while (1)
+	{
+	  memset (lim_states, '\0',
+		  sizeof (re_dfastate_t *) * (match_last + 1));
+	  sift_ctx_init (&sctx, sifted_states, lim_states, halt_node,
+			 match_last);
+	  ret = sift_states_backward (mctx, &sctx);
+	  re_node_set_free (&sctx.limits);
+	  if (BE (ret != REG_NOERROR, 0))
+	      goto free_return;
+	  if (sifted_states[0] != NULL || lim_states[0] != NULL)
+	    break;
+	  do
+	    {
+	      --match_last;
+	      if (match_last < 0)
+		{
+		  ret = REG_NOMATCH;
+		  goto free_return;
+		}
+	    } while (mctx->state_log[match_last] == NULL
+		     || !mctx->state_log[match_last]->halt);
+	  halt_node = check_halt_state_context (mctx,
+						mctx->state_log[match_last],
+						match_last);
+	}
+      ret = merge_state_array (dfa, sifted_states, lim_states,
+			       match_last + 1);
+      re_free (lim_states);
+      lim_states = NULL;
+      if (BE (ret != REG_NOERROR, 0))
+	goto free_return;
+    }
+  else
+    {
+      sift_ctx_init (&sctx, sifted_states, lim_states, halt_node, match_last);
+      ret = sift_states_backward (mctx, &sctx);
+      re_node_set_free (&sctx.limits);
+      if (BE (ret != REG_NOERROR, 0))
+	goto free_return;
+      if (sifted_states[0] == NULL)
+	{
+	  ret = REG_NOMATCH;
+	  goto free_return;
+	}
+    }
+  re_free (mctx->state_log);
+  mctx->state_log = sifted_states;
+  sifted_states = NULL;
+  mctx->last_node = halt_node;
+  mctx->match_last = match_last;
+  ret = REG_NOERROR;
+ free_return:
+  re_free (sifted_states);
+  re_free (lim_states);
+  return ret;
+}
+
+/* Acquire an initial state and return it.
+   We must select appropriate initial state depending on the context,
+   since initial states may have constraints like "\<", "^", etc..  */
+
+static inline re_dfastate_t *
+__attribute__ ((always_inline))
+acquire_init_state_context (reg_errcode_t *err, const re_match_context_t *mctx,
+			    Idx idx)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  if (dfa->init_state->has_constraint)
+    {
+      unsigned int context;
+      context = re_string_context_at (&mctx->input, idx - 1, mctx->eflags);
+      if (IS_WORD_CONTEXT (context))
+	return dfa->init_state_word;
+      else if (IS_ORDINARY_CONTEXT (context))
+	return dfa->init_state;
+      else if (IS_BEGBUF_CONTEXT (context) && IS_NEWLINE_CONTEXT (context))
+	return dfa->init_state_begbuf;
+      else if (IS_NEWLINE_CONTEXT (context))
+	return dfa->init_state_nl;
+      else if (IS_BEGBUF_CONTEXT (context))
+	{
+	  /* It is relatively rare case, then calculate on demand.  */
+	  return re_acquire_state_context (err, dfa,
+					   dfa->init_state->entrance_nodes,
+					   context);
+	}
+      else
+	/* Must not happen?  */
+	return dfa->init_state;
+    }
+  else
+    return dfa->init_state;
+}
+
+/* Check whether the regular expression match input string INPUT or not,
+   and return the index where the matching end.  Return -1 if
+   there is no match, and return -2 in case of an error.
+   FL_LONGEST_MATCH means we want the POSIX longest matching.
+   If P_MATCH_FIRST is not NULL, and the match fails, it is set to the
+   next place where we may want to try matching.
+   Note that the matcher assumes that the matching starts from the current
+   index of the buffer.  */
+
+static Idx
+__attribute_warn_unused_result__
+check_matching (re_match_context_t *mctx, bool fl_longest_match,
+		Idx *p_match_first)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  reg_errcode_t err;
+  Idx match = 0;
+  Idx match_last = -1;
+  Idx cur_str_idx = re_string_cur_idx (&mctx->input);
+  re_dfastate_t *cur_state;
+  bool at_init_state = p_match_first != NULL;
+  Idx next_start_idx = cur_str_idx;
+
+  err = REG_NOERROR;
+  cur_state = acquire_init_state_context (&err, mctx, cur_str_idx);
+  /* An initial state must not be NULL (invalid).  */
+  if (BE (cur_state == NULL, 0))
+    {
+      assert (err == REG_ESPACE);
+      return -2;
+    }
+
+  if (mctx->state_log != NULL)
+    {
+      mctx->state_log[cur_str_idx] = cur_state;
+
+      /* Check OP_OPEN_SUBEXP in the initial state in case that we use them
+	 later.  E.g. Processing back references.  */
+      if (BE (dfa->nbackref, 0))
+	{
+	  at_init_state = false;
+	  err = check_subexp_matching_top (mctx, &cur_state->nodes, 0);
+	  if (BE (err != REG_NOERROR, 0))
+	    return err;
+
+	  if (cur_state->has_backref)
+	    {
+	      err = transit_state_bkref (mctx, &cur_state->nodes);
+	      if (BE (err != REG_NOERROR, 0))
+		return err;
+	    }
+	}
+    }
+
+  /* If the RE accepts NULL string.  */
+  if (BE (cur_state->halt, 0))
+    {
+      if (!cur_state->has_constraint
+	  || check_halt_state_context (mctx, cur_state, cur_str_idx))
+	{
+	  if (!fl_longest_match)
+	    return cur_str_idx;
+	  else
+	    {
+	      match_last = cur_str_idx;
+	      match = 1;
+	    }
+	}
+    }
+
+  while (!re_string_eoi (&mctx->input))
+    {
+      re_dfastate_t *old_state = cur_state;
+      Idx next_char_idx = re_string_cur_idx (&mctx->input) + 1;
+
+      if ((BE (next_char_idx >= mctx->input.bufs_len, 0)
+	   && mctx->input.bufs_len < mctx->input.len)
+	  || (BE (next_char_idx >= mctx->input.valid_len, 0)
+	      && mctx->input.valid_len < mctx->input.len))
+	{
+	  err = extend_buffers (mctx, next_char_idx + 1);
+	  if (BE (err != REG_NOERROR, 0))
+	    {
+	      assert (err == REG_ESPACE);
+	      return -2;
+	    }
+	}
+
+      cur_state = transit_state (&err, mctx, cur_state);
+      if (mctx->state_log != NULL)
+	cur_state = merge_state_with_log (&err, mctx, cur_state);
+
+      if (cur_state == NULL)
+	{
+	  /* Reached the invalid state or an error.  Try to recover a valid
+	     state using the state log, if available and if we have not
+	     already found a valid (even if not the longest) match.  */
+	  if (BE (err != REG_NOERROR, 0))
+	    return -2;
+
+	  if (mctx->state_log == NULL
+	      || (match && !fl_longest_match)
+	      || (cur_state = find_recover_state (&err, mctx)) == NULL)
+	    break;
+	}
+
+      if (BE (at_init_state, 0))
+	{
+	  if (old_state == cur_state)
+	    next_start_idx = next_char_idx;
+	  else
+	    at_init_state = false;
+	}
+
+      if (cur_state->halt)
+	{
+	  /* Reached a halt state.
+	     Check the halt state can satisfy the current context.  */
+	  if (!cur_state->has_constraint
+	      || check_halt_state_context (mctx, cur_state,
+					   re_string_cur_idx (&mctx->input)))
+	    {
+	      /* We found an appropriate halt state.  */
+	      match_last = re_string_cur_idx (&mctx->input);
+	      match = 1;
+
+	      /* We found a match, do not modify match_first below.  */
+	      p_match_first = NULL;
+	      if (!fl_longest_match)
+		break;
+	    }
+	}
+    }
+
+  if (p_match_first)
+    *p_match_first += next_start_idx;
+
+  return match_last;
+}
+
+/* Check NODE match the current context.  */
+
+static bool
+check_halt_node_context (const re_dfa_t *dfa, Idx node, unsigned int context)
+{
+  re_token_type_t type = dfa->nodes[node].type;
+  unsigned int constraint = dfa->nodes[node].constraint;
+  if (type != END_OF_RE)
+    return false;
+  if (!constraint)
+    return true;
+  if (NOT_SATISFY_NEXT_CONSTRAINT (constraint, context))
+    return false;
+  return true;
+}
+
+/* Check the halt state STATE match the current context.
+   Return 0 if not match, if the node, STATE has, is a halt node and
+   match the context, return the node.  */
+
+static Idx
+check_halt_state_context (const re_match_context_t *mctx,
+			  const re_dfastate_t *state, Idx idx)
+{
+  Idx i;
+  unsigned int context;
+#ifdef DEBUG
+  assert (state->halt);
+#endif
+  context = re_string_context_at (&mctx->input, idx, mctx->eflags);
+  for (i = 0; i < state->nodes.nelem; ++i)
+    if (check_halt_node_context (mctx->dfa, state->nodes.elems[i], context))
+      return state->nodes.elems[i];
+  return 0;
+}
+
+/* Compute the next node to which "NFA" transit from NODE("NFA" is a NFA
+   corresponding to the DFA).
+   Return the destination node, and update EPS_VIA_NODES;
+   return -1 in case of errors.  */
+
+static Idx
+proceed_next_node (const re_match_context_t *mctx, Idx nregs, regmatch_t *regs,
+		   Idx *pidx, Idx node, re_node_set *eps_via_nodes,
+		   struct re_fail_stack_t *fs)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  Idx i;
+  bool ok;
+  if (IS_EPSILON_NODE (dfa->nodes[node].type))
+    {
+      re_node_set *cur_nodes = &mctx->state_log[*pidx]->nodes;
+      re_node_set *edests = &dfa->edests[node];
+      Idx dest_node;
+      ok = re_node_set_insert (eps_via_nodes, node);
+      if (BE (! ok, 0))
+	return -2;
+      /* Pick up a valid destination, or return -1 if none
+	 is found.  */
+      for (dest_node = -1, i = 0; i < edests->nelem; ++i)
+	{
+	  Idx candidate = edests->elems[i];
+	  if (!re_node_set_contains (cur_nodes, candidate))
+	    continue;
+          if (dest_node == -1)
+	    dest_node = candidate;
+
+	  else
+	    {
+	      /* In order to avoid infinite loop like "(a*)*", return the second
+		 epsilon-transition if the first was already considered.  */
+	      if (re_node_set_contains (eps_via_nodes, dest_node))
+		return candidate;
+
+	      /* Otherwise, push the second epsilon-transition on the fail stack.  */
+	      else if (fs != NULL
+		       && push_fail_stack (fs, *pidx, candidate, nregs, regs,
+					   eps_via_nodes))
+		return -2;
+
+	      /* We know we are going to exit.  */
+	      break;
+	    }
+	}
+      return dest_node;
+    }
+  else
+    {
+      Idx naccepted = 0;
+      re_token_type_t type = dfa->nodes[node].type;
+
+#ifdef RE_ENABLE_I18N
+      if (dfa->nodes[node].accept_mb)
+	naccepted = check_node_accept_bytes (dfa, node, &mctx->input, *pidx);
+      else
+#endif /* RE_ENABLE_I18N */
+      if (type == OP_BACK_REF)
+	{
+	  Idx subexp_idx = dfa->nodes[node].opr.idx + 1;
+	  naccepted = regs[subexp_idx].rm_eo - regs[subexp_idx].rm_so;
+	  if (fs != NULL)
+	    {
+	      if (regs[subexp_idx].rm_so == -1 || regs[subexp_idx].rm_eo == -1)
+		return -1;
+	      else if (naccepted)
+		{
+		  char *buf = (char *) re_string_get_buffer (&mctx->input);
+		  if (memcmp (buf + regs[subexp_idx].rm_so, buf + *pidx,
+			      naccepted) != 0)
+		    return -1;
+		}
+	    }
+
+	  if (naccepted == 0)
+	    {
+	      Idx dest_node;
+	      ok = re_node_set_insert (eps_via_nodes, node);
+	      if (BE (! ok, 0))
+		return -2;
+	      dest_node = dfa->edests[node].elems[0];
+	      if (re_node_set_contains (&mctx->state_log[*pidx]->nodes,
+					dest_node))
+		return dest_node;
+	    }
+	}
+
+      if (naccepted != 0
+	  || check_node_accept (mctx, dfa->nodes + node, *pidx))
+	{
+	  Idx dest_node = dfa->nexts[node];
+	  *pidx = (naccepted == 0) ? *pidx + 1 : *pidx + naccepted;
+	  if (fs && (*pidx > mctx->match_last || mctx->state_log[*pidx] == NULL
+		     || !re_node_set_contains (&mctx->state_log[*pidx]->nodes,
+					       dest_node)))
+	    return -1;
+	  re_node_set_empty (eps_via_nodes);
+	  return dest_node;
+	}
+    }
+  return -1;
+}
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+push_fail_stack (struct re_fail_stack_t *fs, Idx str_idx, Idx dest_node,
+		 Idx nregs, regmatch_t *regs, re_node_set *eps_via_nodes)
+{
+  reg_errcode_t err;
+  Idx num = fs->num++;
+  if (fs->num == fs->alloc)
+    {
+      struct re_fail_stack_ent_t *new_array;
+      new_array = re_realloc (fs->stack, struct re_fail_stack_ent_t,
+                              fs->alloc * 2);
+      if (new_array == NULL)
+	return REG_ESPACE;
+      fs->alloc *= 2;
+      fs->stack = new_array;
+    }
+  fs->stack[num].idx = str_idx;
+  fs->stack[num].node = dest_node;
+  fs->stack[num].regs = re_malloc (regmatch_t, nregs);
+  if (fs->stack[num].regs == NULL)
+    return REG_ESPACE;
+  memcpy (fs->stack[num].regs, regs, sizeof (regmatch_t) * nregs);
+  err = re_node_set_init_copy (&fs->stack[num].eps_via_nodes, eps_via_nodes);
+  return err;
+}
+
+static Idx
+pop_fail_stack (struct re_fail_stack_t *fs, Idx *pidx, Idx nregs,
+		regmatch_t *regs, re_node_set *eps_via_nodes)
+{
+  Idx num = --fs->num;
+  assert (num >= 0);
+  *pidx = fs->stack[num].idx;
+  memcpy (regs, fs->stack[num].regs, sizeof (regmatch_t) * nregs);
+  re_node_set_free (eps_via_nodes);
+  re_free (fs->stack[num].regs);
+  *eps_via_nodes = fs->stack[num].eps_via_nodes;
+  return fs->stack[num].node;
+}
+
+/* Set the positions where the subexpressions are starts/ends to registers
+   PMATCH.
+   Note: We assume that pmatch[0] is already set, and
+   pmatch[i].rm_so == pmatch[i].rm_eo == -1 for 0 < i < nmatch.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
+	  regmatch_t *pmatch, bool fl_backtrack)
+{
+  const re_dfa_t *dfa = preg->buffer;
+  Idx idx, cur_node;
+  re_node_set eps_via_nodes;
+  struct re_fail_stack_t *fs;
+  struct re_fail_stack_t fs_body = { 0, 2, NULL };
+  regmatch_t *prev_idx_match;
+  bool prev_idx_match_malloced = false;
+
+#ifdef DEBUG
+  assert (nmatch > 1);
+  assert (mctx->state_log != NULL);
+#endif
+  if (fl_backtrack)
+    {
+      fs = &fs_body;
+      fs->stack = re_malloc (struct re_fail_stack_ent_t, fs->alloc);
+      if (fs->stack == NULL)
+	return REG_ESPACE;
+    }
+  else
+    fs = NULL;
+
+  cur_node = dfa->init_node;
+  re_node_set_init_empty (&eps_via_nodes);
+
+  if (__libc_use_alloca (nmatch * sizeof (regmatch_t)))
+    prev_idx_match = (regmatch_t *) alloca (nmatch * sizeof (regmatch_t));
+  else
+    {
+      prev_idx_match = re_malloc (regmatch_t, nmatch);
+      if (prev_idx_match == NULL)
+	{
+	  free_fail_stack_return (fs);
+	  return REG_ESPACE;
+	}
+      prev_idx_match_malloced = true;
+    }
+  memcpy (prev_idx_match, pmatch, sizeof (regmatch_t) * nmatch);
+
+  for (idx = pmatch[0].rm_so; idx <= pmatch[0].rm_eo ;)
+    {
+      update_regs (dfa, pmatch, prev_idx_match, cur_node, idx, nmatch);
+
+      if (idx == pmatch[0].rm_eo && cur_node == mctx->last_node)
+	{
+	  Idx reg_idx;
+	  if (fs)
+	    {
+	      for (reg_idx = 0; reg_idx < nmatch; ++reg_idx)
+		if (pmatch[reg_idx].rm_so > -1 && pmatch[reg_idx].rm_eo == -1)
+		  break;
+	      if (reg_idx == nmatch)
+		{
+		  re_node_set_free (&eps_via_nodes);
+		  if (prev_idx_match_malloced)
+		    re_free (prev_idx_match);
+		  return free_fail_stack_return (fs);
+		}
+	      cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
+					 &eps_via_nodes);
+	    }
+	  else
+	    {
+	      re_node_set_free (&eps_via_nodes);
+	      if (prev_idx_match_malloced)
+		re_free (prev_idx_match);
+	      return REG_NOERROR;
+	    }
+	}
+
+      /* Proceed to next node.  */
+      cur_node = proceed_next_node (mctx, nmatch, pmatch, &idx, cur_node,
+				    &eps_via_nodes, fs);
+
+      if (BE (cur_node < 0, 0))
+	{
+	  if (BE (cur_node == -2, 0))
+	    {
+	      re_node_set_free (&eps_via_nodes);
+	      if (prev_idx_match_malloced)
+		re_free (prev_idx_match);
+	      free_fail_stack_return (fs);
+	      return REG_ESPACE;
+	    }
+	  if (fs)
+	    cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
+				       &eps_via_nodes);
+	  else
+	    {
+	      re_node_set_free (&eps_via_nodes);
+	      if (prev_idx_match_malloced)
+		re_free (prev_idx_match);
+	      return REG_NOMATCH;
+	    }
+	}
+    }
+  re_node_set_free (&eps_via_nodes);
+  if (prev_idx_match_malloced)
+    re_free (prev_idx_match);
+  return free_fail_stack_return (fs);
+}
+
+static reg_errcode_t
+free_fail_stack_return (struct re_fail_stack_t *fs)
+{
+  if (fs)
+    {
+      Idx fs_idx;
+      for (fs_idx = 0; fs_idx < fs->num; ++fs_idx)
+	{
+	  re_node_set_free (&fs->stack[fs_idx].eps_via_nodes);
+	  re_free (fs->stack[fs_idx].regs);
+	}
+      re_free (fs->stack);
+    }
+  return REG_NOERROR;
+}
+
+static void
+update_regs (const re_dfa_t *dfa, regmatch_t *pmatch,
+	     regmatch_t *prev_idx_match, Idx cur_node, Idx cur_idx, Idx nmatch)
+{
+  int type = dfa->nodes[cur_node].type;
+  if (type == OP_OPEN_SUBEXP)
+    {
+      Idx reg_num = dfa->nodes[cur_node].opr.idx + 1;
+
+      /* We are at the first node of this sub expression.  */
+      if (reg_num < nmatch)
+	{
+	  pmatch[reg_num].rm_so = cur_idx;
+	  pmatch[reg_num].rm_eo = -1;
+	}
+    }
+  else if (type == OP_CLOSE_SUBEXP)
+    {
+      Idx reg_num = dfa->nodes[cur_node].opr.idx + 1;
+      if (reg_num < nmatch)
+	{
+	  /* We are at the last node of this sub expression.  */
+	  if (pmatch[reg_num].rm_so < cur_idx)
+	    {
+	      pmatch[reg_num].rm_eo = cur_idx;
+	      /* This is a non-empty match or we are not inside an optional
+		 subexpression.  Accept this right away.  */
+	      memcpy (prev_idx_match, pmatch, sizeof (regmatch_t) * nmatch);
+	    }
+	  else
+	    {
+	      if (dfa->nodes[cur_node].opt_subexp
+		  && prev_idx_match[reg_num].rm_so != -1)
+		/* We transited through an empty match for an optional
+		   subexpression, like (a?)*, and this is not the subexp's
+		   first match.  Copy back the old content of the registers
+		   so that matches of an inner subexpression are undone as
+		   well, like in ((a?))*.  */
+		memcpy (pmatch, prev_idx_match, sizeof (regmatch_t) * nmatch);
+	      else
+		/* We completed a subexpression, but it may be part of
+		   an optional one, so do not update PREV_IDX_MATCH.  */
+		pmatch[reg_num].rm_eo = cur_idx;
+	    }
+	}
+    }
+}
+
+/* This function checks the STATE_LOG from the SCTX->last_str_idx to 0
+   and sift the nodes in each states according to the following rules.
+   Updated state_log will be wrote to STATE_LOG.
+
+   Rules: We throw away the Node 'a' in the STATE_LOG[STR_IDX] if...
+     1. When STR_IDX == MATCH_LAST(the last index in the state_log):
+	If 'a' isn't the LAST_NODE and 'a' can't epsilon transit to
+	the LAST_NODE, we throw away the node 'a'.
+     2. When 0 <= STR_IDX < MATCH_LAST and 'a' accepts
+	string 's' and transit to 'b':
+	i. If 'b' isn't in the STATE_LOG[STR_IDX+strlen('s')], we throw
+	   away the node 'a'.
+	ii. If 'b' is in the STATE_LOG[STR_IDX+strlen('s')] but 'b' is
+	    thrown away, we throw away the node 'a'.
+     3. When 0 <= STR_IDX < MATCH_LAST and 'a' epsilon transit to 'b':
+	i. If 'b' isn't in the STATE_LOG[STR_IDX], we throw away the
+	   node 'a'.
+	ii. If 'b' is in the STATE_LOG[STR_IDX] but 'b' is thrown away,
+	    we throw away the node 'a'.  */
+
+#define STATE_NODE_CONTAINS(state,node) \
+  ((state) != NULL && re_node_set_contains (&(state)->nodes, node))
+
+static reg_errcode_t
+sift_states_backward (const re_match_context_t *mctx, re_sift_context_t *sctx)
+{
+  reg_errcode_t err;
+  int null_cnt = 0;
+  Idx str_idx = sctx->last_str_idx;
+  re_node_set cur_dest;
+
+#ifdef DEBUG
+  assert (mctx->state_log != NULL && mctx->state_log[str_idx] != NULL);
+#endif
+
+  /* Build sifted state_log[str_idx].  It has the nodes which can epsilon
+     transit to the last_node and the last_node itself.  */
+  err = re_node_set_init_1 (&cur_dest, sctx->last_node);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+  err = update_cur_sifted_state (mctx, sctx, str_idx, &cur_dest);
+  if (BE (err != REG_NOERROR, 0))
+    goto free_return;
+
+  /* Then check each states in the state_log.  */
+  while (str_idx > 0)
+    {
+      /* Update counters.  */
+      null_cnt = (sctx->sifted_states[str_idx] == NULL) ? null_cnt + 1 : 0;
+      if (null_cnt > mctx->max_mb_elem_len)
+	{
+	  memset (sctx->sifted_states, '\0',
+		  sizeof (re_dfastate_t *) * str_idx);
+	  re_node_set_free (&cur_dest);
+	  return REG_NOERROR;
+	}
+      re_node_set_empty (&cur_dest);
+      --str_idx;
+
+      if (mctx->state_log[str_idx])
+	{
+	  err = build_sifted_states (mctx, sctx, str_idx, &cur_dest);
+	  if (BE (err != REG_NOERROR, 0))
+	    goto free_return;
+	}
+
+      /* Add all the nodes which satisfy the following conditions:
+	 - It can epsilon transit to a node in CUR_DEST.
+	 - It is in CUR_SRC.
+	 And update state_log.  */
+      err = update_cur_sifted_state (mctx, sctx, str_idx, &cur_dest);
+      if (BE (err != REG_NOERROR, 0))
+	goto free_return;
+    }
+  err = REG_NOERROR;
+ free_return:
+  re_node_set_free (&cur_dest);
+  return err;
+}
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+build_sifted_states (const re_match_context_t *mctx, re_sift_context_t *sctx,
+		     Idx str_idx, re_node_set *cur_dest)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  const re_node_set *cur_src = &mctx->state_log[str_idx]->non_eps_nodes;
+  Idx i;
+
+  /* Then build the next sifted state.
+     We build the next sifted state on 'cur_dest', and update
+     'sifted_states[str_idx]' with 'cur_dest'.
+     Note:
+     'cur_dest' is the sifted state from 'state_log[str_idx + 1]'.
+     'cur_src' points the node_set of the old 'state_log[str_idx]'
+     (with the epsilon nodes pre-filtered out).  */
+  for (i = 0; i < cur_src->nelem; i++)
+    {
+      Idx prev_node = cur_src->elems[i];
+      int naccepted = 0;
+      bool ok;
+
+#ifdef DEBUG
+      re_token_type_t type = dfa->nodes[prev_node].type;
+      assert (!IS_EPSILON_NODE (type));
+#endif
+#ifdef RE_ENABLE_I18N
+      /* If the node may accept "multi byte".  */
+      if (dfa->nodes[prev_node].accept_mb)
+	naccepted = sift_states_iter_mb (mctx, sctx, prev_node,
+					 str_idx, sctx->last_str_idx);
+#endif /* RE_ENABLE_I18N */
+
+      /* We don't check backreferences here.
+	 See update_cur_sifted_state().  */
+      if (!naccepted
+	  && check_node_accept (mctx, dfa->nodes + prev_node, str_idx)
+	  && STATE_NODE_CONTAINS (sctx->sifted_states[str_idx + 1],
+				  dfa->nexts[prev_node]))
+	naccepted = 1;
+
+      if (naccepted == 0)
+	continue;
+
+      if (sctx->limits.nelem)
+	{
+	  Idx to_idx = str_idx + naccepted;
+	  if (check_dst_limits (mctx, &sctx->limits,
+				dfa->nexts[prev_node], to_idx,
+				prev_node, str_idx))
+	    continue;
+	}
+      ok = re_node_set_insert (cur_dest, prev_node);
+      if (BE (! ok, 0))
+	return REG_ESPACE;
+    }
+
+  return REG_NOERROR;
+}
+
+/* Helper functions.  */
+
+static reg_errcode_t
+clean_state_log_if_needed (re_match_context_t *mctx, Idx next_state_log_idx)
+{
+  Idx top = mctx->state_log_top;
+
+  if ((next_state_log_idx >= mctx->input.bufs_len
+       && mctx->input.bufs_len < mctx->input.len)
+      || (next_state_log_idx >= mctx->input.valid_len
+	  && mctx->input.valid_len < mctx->input.len))
+    {
+      reg_errcode_t err;
+      err = extend_buffers (mctx, next_state_log_idx + 1);
+      if (BE (err != REG_NOERROR, 0))
+	return err;
+    }
+
+  if (top < next_state_log_idx)
+    {
+      memset (mctx->state_log + top + 1, '\0',
+	      sizeof (re_dfastate_t *) * (next_state_log_idx - top));
+      mctx->state_log_top = next_state_log_idx;
+    }
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+merge_state_array (const re_dfa_t *dfa, re_dfastate_t **dst,
+		   re_dfastate_t **src, Idx num)
+{
+  Idx st_idx;
+  reg_errcode_t err;
+  for (st_idx = 0; st_idx < num; ++st_idx)
+    {
+      if (dst[st_idx] == NULL)
+	dst[st_idx] = src[st_idx];
+      else if (src[st_idx] != NULL)
+	{
+	  re_node_set merged_set;
+	  err = re_node_set_init_union (&merged_set, &dst[st_idx]->nodes,
+					&src[st_idx]->nodes);
+	  if (BE (err != REG_NOERROR, 0))
+	    return err;
+	  dst[st_idx] = re_acquire_state (&err, dfa, &merged_set);
+	  re_node_set_free (&merged_set);
+	  if (BE (err != REG_NOERROR, 0))
+	    return err;
+	}
+    }
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+update_cur_sifted_state (const re_match_context_t *mctx,
+			 re_sift_context_t *sctx, Idx str_idx,
+			 re_node_set *dest_nodes)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  reg_errcode_t err = REG_NOERROR;
+  const re_node_set *candidates;
+  candidates = ((mctx->state_log[str_idx] == NULL) ? NULL
+		: &mctx->state_log[str_idx]->nodes);
+
+  if (dest_nodes->nelem == 0)
+    sctx->sifted_states[str_idx] = NULL;
+  else
+    {
+      if (candidates)
+	{
+	  /* At first, add the nodes which can epsilon transit to a node in
+	     DEST_NODE.  */
+	  err = add_epsilon_src_nodes (dfa, dest_nodes, candidates);
+	  if (BE (err != REG_NOERROR, 0))
+	    return err;
+
+	  /* Then, check the limitations in the current sift_context.  */
+	  if (sctx->limits.nelem)
+	    {
+	      err = check_subexp_limits (dfa, dest_nodes, candidates, &sctx->limits,
+					 mctx->bkref_ents, str_idx);
+	      if (BE (err != REG_NOERROR, 0))
+		return err;
+	    }
+	}
+
+      sctx->sifted_states[str_idx] = re_acquire_state (&err, dfa, dest_nodes);
+      if (BE (err != REG_NOERROR, 0))
+	return err;
+    }
+
+  if (candidates && mctx->state_log[str_idx]->has_backref)
+    {
+      err = sift_states_bkref (mctx, sctx, str_idx, candidates);
+      if (BE (err != REG_NOERROR, 0))
+	return err;
+    }
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+add_epsilon_src_nodes (const re_dfa_t *dfa, re_node_set *dest_nodes,
+		       const re_node_set *candidates)
+{
+  reg_errcode_t err = REG_NOERROR;
+  Idx i;
+
+  re_dfastate_t *state = re_acquire_state (&err, dfa, dest_nodes);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+
+  if (!state->inveclosure.alloc)
+    {
+      err = re_node_set_alloc (&state->inveclosure, dest_nodes->nelem);
+      if (BE (err != REG_NOERROR, 0))
+	return REG_ESPACE;
+      for (i = 0; i < dest_nodes->nelem; i++)
+	{
+	  err = re_node_set_merge (&state->inveclosure,
+				   dfa->inveclosures + dest_nodes->elems[i]);
+	  if (BE (err != REG_NOERROR, 0))
+	    return REG_ESPACE;
+	}
+    }
+  return re_node_set_add_intersect (dest_nodes, candidates,
+				    &state->inveclosure);
+}
+
+static reg_errcode_t
+sub_epsilon_src_nodes (const re_dfa_t *dfa, Idx node, re_node_set *dest_nodes,
+		       const re_node_set *candidates)
+{
+    Idx ecl_idx;
+    reg_errcode_t err;
+    re_node_set *inv_eclosure = dfa->inveclosures + node;
+    re_node_set except_nodes;
+    re_node_set_init_empty (&except_nodes);
+    for (ecl_idx = 0; ecl_idx < inv_eclosure->nelem; ++ecl_idx)
+      {
+	Idx cur_node = inv_eclosure->elems[ecl_idx];
+	if (cur_node == node)
+	  continue;
+	if (IS_EPSILON_NODE (dfa->nodes[cur_node].type))
+	  {
+	    Idx edst1 = dfa->edests[cur_node].elems[0];
+	    Idx edst2 = ((dfa->edests[cur_node].nelem > 1)
+			 ? dfa->edests[cur_node].elems[1] : -1);
+	    if ((!re_node_set_contains (inv_eclosure, edst1)
+		 && re_node_set_contains (dest_nodes, edst1))
+		|| (edst2 > 0
+		    && !re_node_set_contains (inv_eclosure, edst2)
+		    && re_node_set_contains (dest_nodes, edst2)))
+	      {
+		err = re_node_set_add_intersect (&except_nodes, candidates,
+						 dfa->inveclosures + cur_node);
+		if (BE (err != REG_NOERROR, 0))
+		  {
+		    re_node_set_free (&except_nodes);
+		    return err;
+		  }
+	      }
+	  }
+      }
+    for (ecl_idx = 0; ecl_idx < inv_eclosure->nelem; ++ecl_idx)
+      {
+	Idx cur_node = inv_eclosure->elems[ecl_idx];
+	if (!re_node_set_contains (&except_nodes, cur_node))
+	  {
+	    Idx idx = re_node_set_contains (dest_nodes, cur_node) - 1;
+	    re_node_set_remove_at (dest_nodes, idx);
+	  }
+      }
+    re_node_set_free (&except_nodes);
+    return REG_NOERROR;
+}
+
+static bool
+check_dst_limits (const re_match_context_t *mctx, const re_node_set *limits,
+		  Idx dst_node, Idx dst_idx, Idx src_node, Idx src_idx)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  Idx lim_idx, src_pos, dst_pos;
+
+  Idx dst_bkref_idx = search_cur_bkref_entry (mctx, dst_idx);
+  Idx src_bkref_idx = search_cur_bkref_entry (mctx, src_idx);
+  for (lim_idx = 0; lim_idx < limits->nelem; ++lim_idx)
+    {
+      Idx subexp_idx;
+      struct re_backref_cache_entry *ent;
+      ent = mctx->bkref_ents + limits->elems[lim_idx];
+      subexp_idx = dfa->nodes[ent->node].opr.idx;
+
+      dst_pos = check_dst_limits_calc_pos (mctx, limits->elems[lim_idx],
+					   subexp_idx, dst_node, dst_idx,
+					   dst_bkref_idx);
+      src_pos = check_dst_limits_calc_pos (mctx, limits->elems[lim_idx],
+					   subexp_idx, src_node, src_idx,
+					   src_bkref_idx);
+
+      /* In case of:
+	 <src> <dst> ( <subexp> )
+	 ( <subexp> ) <src> <dst>
+	 ( <subexp1> <src> <subexp2> <dst> <subexp3> )  */
+      if (src_pos == dst_pos)
+	continue; /* This is unrelated limitation.  */
+      else
+	return true;
+    }
+  return false;
+}
+
+static int
+check_dst_limits_calc_pos_1 (const re_match_context_t *mctx, int boundaries,
+			     Idx subexp_idx, Idx from_node, Idx bkref_idx)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  const re_node_set *eclosures = dfa->eclosures + from_node;
+  Idx node_idx;
+
+  /* Else, we are on the boundary: examine the nodes on the epsilon
+     closure.  */
+  for (node_idx = 0; node_idx < eclosures->nelem; ++node_idx)
+    {
+      Idx node = eclosures->elems[node_idx];
+      switch (dfa->nodes[node].type)
+	{
+	case OP_BACK_REF:
+	  if (bkref_idx != -1)
+	    {
+	      struct re_backref_cache_entry *ent = mctx->bkref_ents + bkref_idx;
+	      do
+		{
+		  Idx dst;
+		  int cpos;
+
+		  if (ent->node != node)
+		    continue;
+
+		  if (subexp_idx < BITSET_WORD_BITS
+		      && !(ent->eps_reachable_subexps_map
+			   & ((bitset_word_t) 1 << subexp_idx)))
+		    continue;
+
+		  /* Recurse trying to reach the OP_OPEN_SUBEXP and
+		     OP_CLOSE_SUBEXP cases below.  But, if the
+		     destination node is the same node as the source
+		     node, don't recurse because it would cause an
+		     infinite loop: a regex that exhibits this behavior
+		     is ()\1*\1*  */
+		  dst = dfa->edests[node].elems[0];
+		  if (dst == from_node)
+		    {
+		      if (boundaries & 1)
+			return -1;
+		      else /* if (boundaries & 2) */
+			return 0;
+		    }
+
+		  cpos =
+		    check_dst_limits_calc_pos_1 (mctx, boundaries, subexp_idx,
+						 dst, bkref_idx);
+		  if (cpos == -1 /* && (boundaries & 1) */)
+		    return -1;
+		  if (cpos == 0 && (boundaries & 2))
+		    return 0;
+
+		  if (subexp_idx < BITSET_WORD_BITS)
+		    ent->eps_reachable_subexps_map
+		      &= ~((bitset_word_t) 1 << subexp_idx);
+		}
+	      while (ent++->more);
+	    }
+	  break;
+
+	case OP_OPEN_SUBEXP:
+	  if ((boundaries & 1) && subexp_idx == dfa->nodes[node].opr.idx)
+	    return -1;
+	  break;
+
+	case OP_CLOSE_SUBEXP:
+	  if ((boundaries & 2) && subexp_idx == dfa->nodes[node].opr.idx)
+	    return 0;
+	  break;
+
+	default:
+	    break;
+	}
+    }
+
+  return (boundaries & 2) ? 1 : 0;
+}
+
+static int
+check_dst_limits_calc_pos (const re_match_context_t *mctx, Idx limit,
+			   Idx subexp_idx, Idx from_node, Idx str_idx,
+			   Idx bkref_idx)
+{
+  struct re_backref_cache_entry *lim = mctx->bkref_ents + limit;
+  int boundaries;
+
+  /* If we are outside the range of the subexpression, return -1 or 1.  */
+  if (str_idx < lim->subexp_from)
+    return -1;
+
+  if (lim->subexp_to < str_idx)
+    return 1;
+
+  /* If we are within the subexpression, return 0.  */
+  boundaries = (str_idx == lim->subexp_from);
+  boundaries |= (str_idx == lim->subexp_to) << 1;
+  if (boundaries == 0)
+    return 0;
+
+  /* Else, examine epsilon closure.  */
+  return check_dst_limits_calc_pos_1 (mctx, boundaries, subexp_idx,
+				      from_node, bkref_idx);
+}
+
+/* Check the limitations of sub expressions LIMITS, and remove the nodes
+   which are against limitations from DEST_NODES. */
+
+static reg_errcode_t
+check_subexp_limits (const re_dfa_t *dfa, re_node_set *dest_nodes,
+		     const re_node_set *candidates, re_node_set *limits,
+		     struct re_backref_cache_entry *bkref_ents, Idx str_idx)
+{
+  reg_errcode_t err;
+  Idx node_idx, lim_idx;
+
+  for (lim_idx = 0; lim_idx < limits->nelem; ++lim_idx)
+    {
+      Idx subexp_idx;
+      struct re_backref_cache_entry *ent;
+      ent = bkref_ents + limits->elems[lim_idx];
+
+      if (str_idx <= ent->subexp_from || ent->str_idx < str_idx)
+	continue; /* This is unrelated limitation.  */
+
+      subexp_idx = dfa->nodes[ent->node].opr.idx;
+      if (ent->subexp_to == str_idx)
+	{
+	  Idx ops_node = -1;
+	  Idx cls_node = -1;
+	  for (node_idx = 0; node_idx < dest_nodes->nelem; ++node_idx)
+	    {
+	      Idx node = dest_nodes->elems[node_idx];
+	      re_token_type_t type = dfa->nodes[node].type;
+	      if (type == OP_OPEN_SUBEXP
+		  && subexp_idx == dfa->nodes[node].opr.idx)
+		ops_node = node;
+	      else if (type == OP_CLOSE_SUBEXP
+		       && subexp_idx == dfa->nodes[node].opr.idx)
+		cls_node = node;
+	    }
+
+	  /* Check the limitation of the open subexpression.  */
+	  /* Note that (ent->subexp_to = str_idx != ent->subexp_from).  */
+	  if (ops_node >= 0)
+	    {
+	      err = sub_epsilon_src_nodes (dfa, ops_node, dest_nodes,
+					   candidates);
+	      if (BE (err != REG_NOERROR, 0))
+		return err;
+	    }
+
+	  /* Check the limitation of the close subexpression.  */
+	  if (cls_node >= 0)
+	    for (node_idx = 0; node_idx < dest_nodes->nelem; ++node_idx)
+	      {
+		Idx node = dest_nodes->elems[node_idx];
+		if (!re_node_set_contains (dfa->inveclosures + node,
+					   cls_node)
+		    && !re_node_set_contains (dfa->eclosures + node,
+					      cls_node))
+		  {
+		    /* It is against this limitation.
+		       Remove it form the current sifted state.  */
+		    err = sub_epsilon_src_nodes (dfa, node, dest_nodes,
+						 candidates);
+		    if (BE (err != REG_NOERROR, 0))
+		      return err;
+		    --node_idx;
+		  }
+	      }
+	}
+      else /* (ent->subexp_to != str_idx)  */
+	{
+	  for (node_idx = 0; node_idx < dest_nodes->nelem; ++node_idx)
+	    {
+	      Idx node = dest_nodes->elems[node_idx];
+	      re_token_type_t type = dfa->nodes[node].type;
+	      if (type == OP_CLOSE_SUBEXP || type == OP_OPEN_SUBEXP)
+		{
+		  if (subexp_idx != dfa->nodes[node].opr.idx)
+		    continue;
+		  /* It is against this limitation.
+		     Remove it form the current sifted state.  */
+		  err = sub_epsilon_src_nodes (dfa, node, dest_nodes,
+					       candidates);
+		  if (BE (err != REG_NOERROR, 0))
+		    return err;
+		}
+	    }
+	}
+    }
+  return REG_NOERROR;
+}
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+sift_states_bkref (const re_match_context_t *mctx, re_sift_context_t *sctx,
+		   Idx str_idx, const re_node_set *candidates)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  reg_errcode_t err;
+  Idx node_idx, node;
+  re_sift_context_t local_sctx;
+  Idx first_idx = search_cur_bkref_entry (mctx, str_idx);
+
+  if (first_idx == -1)
+    return REG_NOERROR;
+
+  local_sctx.sifted_states = NULL; /* Mark that it hasn't been initialized.  */
+
+  for (node_idx = 0; node_idx < candidates->nelem; ++node_idx)
+    {
+      Idx enabled_idx;
+      re_token_type_t type;
+      struct re_backref_cache_entry *entry;
+      node = candidates->elems[node_idx];
+      type = dfa->nodes[node].type;
+      /* Avoid infinite loop for the REs like "()\1+".  */
+      if (node == sctx->last_node && str_idx == sctx->last_str_idx)
+	continue;
+      if (type != OP_BACK_REF)
+	continue;
+
+      entry = mctx->bkref_ents + first_idx;
+      enabled_idx = first_idx;
+      do
+	{
+	  Idx subexp_len;
+	  Idx to_idx;
+	  Idx dst_node;
+	  bool ok;
+	  re_dfastate_t *cur_state;
+
+	  if (entry->node != node)
+	    continue;
+	  subexp_len = entry->subexp_to - entry->subexp_from;
+	  to_idx = str_idx + subexp_len;
+	  dst_node = (subexp_len ? dfa->nexts[node]
+		      : dfa->edests[node].elems[0]);
+
+	  if (to_idx > sctx->last_str_idx
+	      || sctx->sifted_states[to_idx] == NULL
+	      || !STATE_NODE_CONTAINS (sctx->sifted_states[to_idx], dst_node)
+	      || check_dst_limits (mctx, &sctx->limits, node,
+				   str_idx, dst_node, to_idx))
+	    continue;
+
+	  if (local_sctx.sifted_states == NULL)
+	    {
+	      local_sctx = *sctx;
+	      err = re_node_set_init_copy (&local_sctx.limits, &sctx->limits);
+	      if (BE (err != REG_NOERROR, 0))
+		goto free_return;
+	    }
+	  local_sctx.last_node = node;
+	  local_sctx.last_str_idx = str_idx;
+	  ok = re_node_set_insert (&local_sctx.limits, enabled_idx);
+	  if (BE (! ok, 0))
+	    {
+	      err = REG_ESPACE;
+	      goto free_return;
+	    }
+	  cur_state = local_sctx.sifted_states[str_idx];
+	  err = sift_states_backward (mctx, &local_sctx);
+	  if (BE (err != REG_NOERROR, 0))
+	    goto free_return;
+	  if (sctx->limited_states != NULL)
+	    {
+	      err = merge_state_array (dfa, sctx->limited_states,
+				       local_sctx.sifted_states,
+				       str_idx + 1);
+	      if (BE (err != REG_NOERROR, 0))
+		goto free_return;
+	    }
+	  local_sctx.sifted_states[str_idx] = cur_state;
+	  re_node_set_remove (&local_sctx.limits, enabled_idx);
+
+	  /* mctx->bkref_ents may have changed, reload the pointer.  */
+	  entry = mctx->bkref_ents + enabled_idx;
+	}
+      while (enabled_idx++, entry++->more);
+    }
+  err = REG_NOERROR;
+ free_return:
+  if (local_sctx.sifted_states != NULL)
+    {
+      re_node_set_free (&local_sctx.limits);
+    }
+
+  return err;
+}
+
+
+#ifdef RE_ENABLE_I18N
+static int
+sift_states_iter_mb (const re_match_context_t *mctx, re_sift_context_t *sctx,
+		     Idx node_idx, Idx str_idx, Idx max_str_idx)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  int naccepted;
+  /* Check the node can accept "multi byte".  */
+  naccepted = check_node_accept_bytes (dfa, node_idx, &mctx->input, str_idx);
+  if (naccepted > 0 && str_idx + naccepted <= max_str_idx &&
+      !STATE_NODE_CONTAINS (sctx->sifted_states[str_idx + naccepted],
+			    dfa->nexts[node_idx]))
+    /* The node can't accept the "multi byte", or the
+       destination was already thrown away, then the node
+       could't accept the current input "multi byte".   */
+    naccepted = 0;
+  /* Otherwise, it is sure that the node could accept
+     'naccepted' bytes input.  */
+  return naccepted;
+}
+#endif /* RE_ENABLE_I18N */
+
+
+/* Functions for state transition.  */
+
+/* Return the next state to which the current state STATE will transit by
+   accepting the current input byte, and update STATE_LOG if necessary.
+   If STATE can accept a multibyte char/collating element/back reference
+   update the destination of STATE_LOG.  */
+
+static re_dfastate_t *
+__attribute_warn_unused_result__
+transit_state (reg_errcode_t *err, re_match_context_t *mctx,
+	       re_dfastate_t *state)
+{
+  re_dfastate_t **trtable;
+  unsigned char ch;
+
+#ifdef RE_ENABLE_I18N
+  /* If the current state can accept multibyte.  */
+  if (BE (state->accept_mb, 0))
+    {
+      *err = transit_state_mb (mctx, state);
+      if (BE (*err != REG_NOERROR, 0))
+	return NULL;
+    }
+#endif /* RE_ENABLE_I18N */
+
+  /* Then decide the next state with the single byte.  */
+#if 0
+  if (0)
+    /* don't use transition table  */
+    return transit_state_sb (err, mctx, state);
+#endif
+
+  /* Use transition table  */
+  ch = re_string_fetch_byte (&mctx->input);
+  for (;;)
+    {
+      trtable = state->trtable;
+      if (BE (trtable != NULL, 1))
+	return trtable[ch];
+
+      trtable = state->word_trtable;
+      if (BE (trtable != NULL, 1))
+	{
+	  unsigned int context;
+	  context
+	    = re_string_context_at (&mctx->input,
+				    re_string_cur_idx (&mctx->input) - 1,
+				    mctx->eflags);
+	  if (IS_WORD_CONTEXT (context))
+	    return trtable[ch + SBC_MAX];
+	  else
+	    return trtable[ch];
+	}
+
+      if (!build_trtable (mctx->dfa, state))
+	{
+	  *err = REG_ESPACE;
+	  return NULL;
+	}
+
+      /* Retry, we now have a transition table.  */
+    }
+}
+
+/* Update the state_log if we need */
+static re_dfastate_t *
+merge_state_with_log (reg_errcode_t *err, re_match_context_t *mctx,
+		      re_dfastate_t *next_state)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  Idx cur_idx = re_string_cur_idx (&mctx->input);
+
+  if (cur_idx > mctx->state_log_top)
+    {
+      mctx->state_log[cur_idx] = next_state;
+      mctx->state_log_top = cur_idx;
+    }
+  else if (mctx->state_log[cur_idx] == 0)
+    {
+      mctx->state_log[cur_idx] = next_state;
+    }
+  else
+    {
+      re_dfastate_t *pstate;
+      unsigned int context;
+      re_node_set next_nodes, *log_nodes, *table_nodes = NULL;
+      /* If (state_log[cur_idx] != 0), it implies that cur_idx is
+	 the destination of a multibyte char/collating element/
+	 back reference.  Then the next state is the union set of
+	 these destinations and the results of the transition table.  */
+      pstate = mctx->state_log[cur_idx];
+      log_nodes = pstate->entrance_nodes;
+      if (next_state != NULL)
+	{
+	  table_nodes = next_state->entrance_nodes;
+	  *err = re_node_set_init_union (&next_nodes, table_nodes,
+					     log_nodes);
+	  if (BE (*err != REG_NOERROR, 0))
+	    return NULL;
+	}
+      else
+	next_nodes = *log_nodes;
+      /* Note: We already add the nodes of the initial state,
+	 then we don't need to add them here.  */
+
+      context = re_string_context_at (&mctx->input,
+				      re_string_cur_idx (&mctx->input) - 1,
+				      mctx->eflags);
+      next_state = mctx->state_log[cur_idx]
+	= re_acquire_state_context (err, dfa, &next_nodes, context);
+      /* We don't need to check errors here, since the return value of
+	 this function is next_state and ERR is already set.  */
+
+      if (table_nodes != NULL)
+	re_node_set_free (&next_nodes);
+    }
+
+  if (BE (dfa->nbackref, 0) && next_state != NULL)
+    {
+      /* Check OP_OPEN_SUBEXP in the current state in case that we use them
+	 later.  We must check them here, since the back references in the
+	 next state might use them.  */
+      *err = check_subexp_matching_top (mctx, &next_state->nodes,
+					cur_idx);
+      if (BE (*err != REG_NOERROR, 0))
+	return NULL;
+
+      /* If the next state has back references.  */
+      if (next_state->has_backref)
+	{
+	  *err = transit_state_bkref (mctx, &next_state->nodes);
+	  if (BE (*err != REG_NOERROR, 0))
+	    return NULL;
+	  next_state = mctx->state_log[cur_idx];
+	}
+    }
+
+  return next_state;
+}
+
+/* Skip bytes in the input that correspond to part of a
+   multi-byte match, then look in the log for a state
+   from which to restart matching.  */
+static re_dfastate_t *
+find_recover_state (reg_errcode_t *err, re_match_context_t *mctx)
+{
+  re_dfastate_t *cur_state;
+  do
+    {
+      Idx max = mctx->state_log_top;
+      Idx cur_str_idx = re_string_cur_idx (&mctx->input);
+
+      do
+	{
+	  if (++cur_str_idx > max)
+	    return NULL;
+	  re_string_skip_bytes (&mctx->input, 1);
+	}
+      while (mctx->state_log[cur_str_idx] == NULL);
+
+      cur_state = merge_state_with_log (err, mctx, NULL);
+    }
+  while (*err == REG_NOERROR && cur_state == NULL);
+  return cur_state;
+}
+
+/* Helper functions for transit_state.  */
+
+/* From the node set CUR_NODES, pick up the nodes whose types are
+   OP_OPEN_SUBEXP and which have corresponding back references in the regular
+   expression. And register them to use them later for evaluating the
+   corresponding back references.  */
+
+static reg_errcode_t
+check_subexp_matching_top (re_match_context_t *mctx, re_node_set *cur_nodes,
+			   Idx str_idx)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  Idx node_idx;
+  reg_errcode_t err;
+
+  /* TODO: This isn't efficient.
+	   Because there might be more than one nodes whose types are
+	   OP_OPEN_SUBEXP and whose index is SUBEXP_IDX, we must check all
+	   nodes.
+	   E.g. RE: (a){2}  */
+  for (node_idx = 0; node_idx < cur_nodes->nelem; ++node_idx)
+    {
+      Idx node = cur_nodes->elems[node_idx];
+      if (dfa->nodes[node].type == OP_OPEN_SUBEXP
+	  && dfa->nodes[node].opr.idx < BITSET_WORD_BITS
+	  && (dfa->used_bkref_map
+	      & ((bitset_word_t) 1 << dfa->nodes[node].opr.idx)))
+	{
+	  err = match_ctx_add_subtop (mctx, node, str_idx);
+	  if (BE (err != REG_NOERROR, 0))
+	    return err;
+	}
+    }
+  return REG_NOERROR;
+}
+
+#if 0
+/* Return the next state to which the current state STATE will transit by
+   accepting the current input byte.  */
+
+static re_dfastate_t *
+transit_state_sb (reg_errcode_t *err, re_match_context_t *mctx,
+		  re_dfastate_t *state)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  re_node_set next_nodes;
+  re_dfastate_t *next_state;
+  Idx node_cnt, cur_str_idx = re_string_cur_idx (&mctx->input);
+  unsigned int context;
+
+  *err = re_node_set_alloc (&next_nodes, state->nodes.nelem + 1);
+  if (BE (*err != REG_NOERROR, 0))
+    return NULL;
+  for (node_cnt = 0; node_cnt < state->nodes.nelem; ++node_cnt)
+    {
+      Idx cur_node = state->nodes.elems[node_cnt];
+      if (check_node_accept (mctx, dfa->nodes + cur_node, cur_str_idx))
+	{
+	  *err = re_node_set_merge (&next_nodes,
+				    dfa->eclosures + dfa->nexts[cur_node]);
+	  if (BE (*err != REG_NOERROR, 0))
+	    {
+	      re_node_set_free (&next_nodes);
+	      return NULL;
+	    }
+	}
+    }
+  context = re_string_context_at (&mctx->input, cur_str_idx, mctx->eflags);
+  next_state = re_acquire_state_context (err, dfa, &next_nodes, context);
+  /* We don't need to check errors here, since the return value of
+     this function is next_state and ERR is already set.  */
+
+  re_node_set_free (&next_nodes);
+  re_string_skip_bytes (&mctx->input, 1);
+  return next_state;
+}
+#endif
+
+#ifdef RE_ENABLE_I18N
+static reg_errcode_t
+transit_state_mb (re_match_context_t *mctx, re_dfastate_t *pstate)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  reg_errcode_t err;
+  Idx i;
+
+  for (i = 0; i < pstate->nodes.nelem; ++i)
+    {
+      re_node_set dest_nodes, *new_nodes;
+      Idx cur_node_idx = pstate->nodes.elems[i];
+      int naccepted;
+      Idx dest_idx;
+      unsigned int context;
+      re_dfastate_t *dest_state;
+
+      if (!dfa->nodes[cur_node_idx].accept_mb)
+	continue;
+
+      if (dfa->nodes[cur_node_idx].constraint)
+	{
+	  context = re_string_context_at (&mctx->input,
+					  re_string_cur_idx (&mctx->input),
+					  mctx->eflags);
+	  if (NOT_SATISFY_NEXT_CONSTRAINT (dfa->nodes[cur_node_idx].constraint,
+					   context))
+	    continue;
+	}
+
+      /* How many bytes the node can accept?  */
+      naccepted = check_node_accept_bytes (dfa, cur_node_idx, &mctx->input,
+					   re_string_cur_idx (&mctx->input));
+      if (naccepted == 0)
+	continue;
+
+      /* The node can accepts 'naccepted' bytes.  */
+      dest_idx = re_string_cur_idx (&mctx->input) + naccepted;
+      mctx->max_mb_elem_len = ((mctx->max_mb_elem_len < naccepted) ? naccepted
+			       : mctx->max_mb_elem_len);
+      err = clean_state_log_if_needed (mctx, dest_idx);
+      if (BE (err != REG_NOERROR, 0))
+	return err;
+#ifdef DEBUG
+      assert (dfa->nexts[cur_node_idx] != -1);
+#endif
+      new_nodes = dfa->eclosures + dfa->nexts[cur_node_idx];
+
+      dest_state = mctx->state_log[dest_idx];
+      if (dest_state == NULL)
+	dest_nodes = *new_nodes;
+      else
+	{
+	  err = re_node_set_init_union (&dest_nodes,
+					dest_state->entrance_nodes, new_nodes);
+	  if (BE (err != REG_NOERROR, 0))
+	    return err;
+	}
+      context = re_string_context_at (&mctx->input, dest_idx - 1,
+				      mctx->eflags);
+      mctx->state_log[dest_idx]
+	= re_acquire_state_context (&err, dfa, &dest_nodes, context);
+      if (dest_state != NULL)
+	re_node_set_free (&dest_nodes);
+      if (BE (mctx->state_log[dest_idx] == NULL && err != REG_NOERROR, 0))
+	return err;
+    }
+  return REG_NOERROR;
+}
+#endif /* RE_ENABLE_I18N */
+
+static reg_errcode_t
+transit_state_bkref (re_match_context_t *mctx, const re_node_set *nodes)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  reg_errcode_t err;
+  Idx i;
+  Idx cur_str_idx = re_string_cur_idx (&mctx->input);
+
+  for (i = 0; i < nodes->nelem; ++i)
+    {
+      Idx dest_str_idx, prev_nelem, bkc_idx;
+      Idx node_idx = nodes->elems[i];
+      unsigned int context;
+      const re_token_t *node = dfa->nodes + node_idx;
+      re_node_set *new_dest_nodes;
+
+      /* Check whether 'node' is a backreference or not.  */
+      if (node->type != OP_BACK_REF)
+	continue;
+
+      if (node->constraint)
+	{
+	  context = re_string_context_at (&mctx->input, cur_str_idx,
+					  mctx->eflags);
+	  if (NOT_SATISFY_NEXT_CONSTRAINT (node->constraint, context))
+	    continue;
+	}
+
+      /* 'node' is a backreference.
+	 Check the substring which the substring matched.  */
+      bkc_idx = mctx->nbkref_ents;
+      err = get_subexp (mctx, node_idx, cur_str_idx);
+      if (BE (err != REG_NOERROR, 0))
+	goto free_return;
+
+      /* And add the epsilon closures (which is 'new_dest_nodes') of
+	 the backreference to appropriate state_log.  */
+#ifdef DEBUG
+      assert (dfa->nexts[node_idx] != -1);
+#endif
+      for (; bkc_idx < mctx->nbkref_ents; ++bkc_idx)
+	{
+	  Idx subexp_len;
+	  re_dfastate_t *dest_state;
+	  struct re_backref_cache_entry *bkref_ent;
+	  bkref_ent = mctx->bkref_ents + bkc_idx;
+	  if (bkref_ent->node != node_idx || bkref_ent->str_idx != cur_str_idx)
+	    continue;
+	  subexp_len = bkref_ent->subexp_to - bkref_ent->subexp_from;
+	  new_dest_nodes = (subexp_len == 0
+			    ? dfa->eclosures + dfa->edests[node_idx].elems[0]
+			    : dfa->eclosures + dfa->nexts[node_idx]);
+	  dest_str_idx = (cur_str_idx + bkref_ent->subexp_to
+			  - bkref_ent->subexp_from);
+	  context = re_string_context_at (&mctx->input, dest_str_idx - 1,
+					  mctx->eflags);
+	  dest_state = mctx->state_log[dest_str_idx];
+	  prev_nelem = ((mctx->state_log[cur_str_idx] == NULL) ? 0
+			: mctx->state_log[cur_str_idx]->nodes.nelem);
+	  /* Add 'new_dest_node' to state_log.  */
+	  if (dest_state == NULL)
+	    {
+	      mctx->state_log[dest_str_idx]
+		= re_acquire_state_context (&err, dfa, new_dest_nodes,
+					    context);
+	      if (BE (mctx->state_log[dest_str_idx] == NULL
+		      && err != REG_NOERROR, 0))
+		goto free_return;
+	    }
+	  else
+	    {
+	      re_node_set dest_nodes;
+	      err = re_node_set_init_union (&dest_nodes,
+					    dest_state->entrance_nodes,
+					    new_dest_nodes);
+	      if (BE (err != REG_NOERROR, 0))
+		{
+		  re_node_set_free (&dest_nodes);
+		  goto free_return;
+		}
+	      mctx->state_log[dest_str_idx]
+		= re_acquire_state_context (&err, dfa, &dest_nodes, context);
+	      re_node_set_free (&dest_nodes);
+	      if (BE (mctx->state_log[dest_str_idx] == NULL
+		      && err != REG_NOERROR, 0))
+		goto free_return;
+	    }
+	  /* We need to check recursively if the backreference can epsilon
+	     transit.  */
+	  if (subexp_len == 0
+	      && mctx->state_log[cur_str_idx]->nodes.nelem > prev_nelem)
+	    {
+	      err = check_subexp_matching_top (mctx, new_dest_nodes,
+					       cur_str_idx);
+	      if (BE (err != REG_NOERROR, 0))
+		goto free_return;
+	      err = transit_state_bkref (mctx, new_dest_nodes);
+	      if (BE (err != REG_NOERROR, 0))
+		goto free_return;
+	    }
+	}
+    }
+  err = REG_NOERROR;
+ free_return:
+  return err;
+}
+
+/* Enumerate all the candidates which the backreference BKREF_NODE can match
+   at BKREF_STR_IDX, and register them by match_ctx_add_entry().
+   Note that we might collect inappropriate candidates here.
+   However, the cost of checking them strictly here is too high, then we
+   delay these checking for prune_impossible_nodes().  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+get_subexp (re_match_context_t *mctx, Idx bkref_node, Idx bkref_str_idx)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  Idx subexp_num, sub_top_idx;
+  const char *buf = (const char *) re_string_get_buffer (&mctx->input);
+  /* Return if we have already checked BKREF_NODE at BKREF_STR_IDX.  */
+  Idx cache_idx = search_cur_bkref_entry (mctx, bkref_str_idx);
+  if (cache_idx != -1)
+    {
+      const struct re_backref_cache_entry *entry
+	= mctx->bkref_ents + cache_idx;
+      do
+	if (entry->node == bkref_node)
+	  return REG_NOERROR; /* We already checked it.  */
+      while (entry++->more);
+    }
+
+  subexp_num = dfa->nodes[bkref_node].opr.idx;
+
+  /* For each sub expression  */
+  for (sub_top_idx = 0; sub_top_idx < mctx->nsub_tops; ++sub_top_idx)
+    {
+      reg_errcode_t err;
+      re_sub_match_top_t *sub_top = mctx->sub_tops[sub_top_idx];
+      re_sub_match_last_t *sub_last;
+      Idx sub_last_idx, sl_str, bkref_str_off;
+
+      if (dfa->nodes[sub_top->node].opr.idx != subexp_num)
+	continue; /* It isn't related.  */
+
+      sl_str = sub_top->str_idx;
+      bkref_str_off = bkref_str_idx;
+      /* At first, check the last node of sub expressions we already
+	 evaluated.  */
+      for (sub_last_idx = 0; sub_last_idx < sub_top->nlasts; ++sub_last_idx)
+	{
+	  regoff_t sl_str_diff;
+	  sub_last = sub_top->lasts[sub_last_idx];
+	  sl_str_diff = sub_last->str_idx - sl_str;
+	  /* The matched string by the sub expression match with the substring
+	     at the back reference?  */
+	  if (sl_str_diff > 0)
+	    {
+	      if (BE (bkref_str_off + sl_str_diff > mctx->input.valid_len, 0))
+		{
+		  /* Not enough chars for a successful match.  */
+		  if (bkref_str_off + sl_str_diff > mctx->input.len)
+		    break;
+
+		  err = clean_state_log_if_needed (mctx,
+						   bkref_str_off
+						   + sl_str_diff);
+		  if (BE (err != REG_NOERROR, 0))
+		    return err;
+		  buf = (const char *) re_string_get_buffer (&mctx->input);
+		}
+	      if (memcmp (buf + bkref_str_off, buf + sl_str, sl_str_diff) != 0)
+		/* We don't need to search this sub expression any more.  */
+		break;
+	    }
+	  bkref_str_off += sl_str_diff;
+	  sl_str += sl_str_diff;
+	  err = get_subexp_sub (mctx, sub_top, sub_last, bkref_node,
+				bkref_str_idx);
+
+	  /* Reload buf, since the preceding call might have reallocated
+	     the buffer.  */
+	  buf = (const char *) re_string_get_buffer (&mctx->input);
+
+	  if (err == REG_NOMATCH)
+	    continue;
+	  if (BE (err != REG_NOERROR, 0))
+	    return err;
+	}
+
+      if (sub_last_idx < sub_top->nlasts)
+	continue;
+      if (sub_last_idx > 0)
+	++sl_str;
+      /* Then, search for the other last nodes of the sub expression.  */
+      for (; sl_str <= bkref_str_idx; ++sl_str)
+	{
+	  Idx cls_node;
+	  regoff_t sl_str_off;
+	  const re_node_set *nodes;
+	  sl_str_off = sl_str - sub_top->str_idx;
+	  /* The matched string by the sub expression match with the substring
+	     at the back reference?  */
+	  if (sl_str_off > 0)
+	    {
+	      if (BE (bkref_str_off >= mctx->input.valid_len, 0))
+		{
+		  /* If we are at the end of the input, we cannot match.  */
+		  if (bkref_str_off >= mctx->input.len)
+		    break;
+
+		  err = extend_buffers (mctx, bkref_str_off + 1);
+		  if (BE (err != REG_NOERROR, 0))
+		    return err;
+
+		  buf = (const char *) re_string_get_buffer (&mctx->input);
+		}
+	      if (buf [bkref_str_off++] != buf[sl_str - 1])
+		break; /* We don't need to search this sub expression
+			  any more.  */
+	    }
+	  if (mctx->state_log[sl_str] == NULL)
+	    continue;
+	  /* Does this state have a ')' of the sub expression?  */
+	  nodes = &mctx->state_log[sl_str]->nodes;
+	  cls_node = find_subexp_node (dfa, nodes, subexp_num,
+				       OP_CLOSE_SUBEXP);
+	  if (cls_node == -1)
+	    continue; /* No.  */
+	  if (sub_top->path == NULL)
+	    {
+	      sub_top->path = calloc (sizeof (state_array_t),
+				      sl_str - sub_top->str_idx + 1);
+	      if (sub_top->path == NULL)
+		return REG_ESPACE;
+	    }
+	  /* Can the OP_OPEN_SUBEXP node arrive the OP_CLOSE_SUBEXP node
+	     in the current context?  */
+	  err = check_arrival (mctx, sub_top->path, sub_top->node,
+			       sub_top->str_idx, cls_node, sl_str,
+			       OP_CLOSE_SUBEXP);
+	  if (err == REG_NOMATCH)
+	      continue;
+	  if (BE (err != REG_NOERROR, 0))
+	      return err;
+	  sub_last = match_ctx_add_sublast (sub_top, cls_node, sl_str);
+	  if (BE (sub_last == NULL, 0))
+	    return REG_ESPACE;
+	  err = get_subexp_sub (mctx, sub_top, sub_last, bkref_node,
+				bkref_str_idx);
+	  if (err == REG_NOMATCH)
+	    continue;
+	}
+    }
+  return REG_NOERROR;
+}
+
+/* Helper functions for get_subexp().  */
+
+/* Check SUB_LAST can arrive to the back reference BKREF_NODE at BKREF_STR.
+   If it can arrive, register the sub expression expressed with SUB_TOP
+   and SUB_LAST.  */
+
+static reg_errcode_t
+get_subexp_sub (re_match_context_t *mctx, const re_sub_match_top_t *sub_top,
+		re_sub_match_last_t *sub_last, Idx bkref_node, Idx bkref_str)
+{
+  reg_errcode_t err;
+  Idx to_idx;
+  /* Can the subexpression arrive the back reference?  */
+  err = check_arrival (mctx, &sub_last->path, sub_last->node,
+		       sub_last->str_idx, bkref_node, bkref_str,
+		       OP_OPEN_SUBEXP);
+  if (err != REG_NOERROR)
+    return err;
+  err = match_ctx_add_entry (mctx, bkref_node, bkref_str, sub_top->str_idx,
+			     sub_last->str_idx);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+  to_idx = bkref_str + sub_last->str_idx - sub_top->str_idx;
+  return clean_state_log_if_needed (mctx, to_idx);
+}
+
+/* Find the first node which is '(' or ')' and whose index is SUBEXP_IDX.
+   Search '(' if FL_OPEN, or search ')' otherwise.
+   TODO: This function isn't efficient...
+	 Because there might be more than one nodes whose types are
+	 OP_OPEN_SUBEXP and whose index is SUBEXP_IDX, we must check all
+	 nodes.
+	 E.g. RE: (a){2}  */
+
+static Idx
+find_subexp_node (const re_dfa_t *dfa, const re_node_set *nodes,
+		  Idx subexp_idx, int type)
+{
+  Idx cls_idx;
+  for (cls_idx = 0; cls_idx < nodes->nelem; ++cls_idx)
+    {
+      Idx cls_node = nodes->elems[cls_idx];
+      const re_token_t *node = dfa->nodes + cls_node;
+      if (node->type == type
+	  && node->opr.idx == subexp_idx)
+	return cls_node;
+    }
+  return -1;
+}
+
+/* Check whether the node TOP_NODE at TOP_STR can arrive to the node
+   LAST_NODE at LAST_STR.  We record the path onto PATH since it will be
+   heavily reused.
+   Return REG_NOERROR if it can arrive, or REG_NOMATCH otherwise.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+check_arrival (re_match_context_t *mctx, state_array_t *path, Idx top_node,
+	       Idx top_str, Idx last_node, Idx last_str, int type)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  reg_errcode_t err = REG_NOERROR;
+  Idx subexp_num, backup_cur_idx, str_idx, null_cnt;
+  re_dfastate_t *cur_state = NULL;
+  re_node_set *cur_nodes, next_nodes;
+  re_dfastate_t **backup_state_log;
+  unsigned int context;
+
+  subexp_num = dfa->nodes[top_node].opr.idx;
+  /* Extend the buffer if we need.  */
+  if (BE (path->alloc < last_str + mctx->max_mb_elem_len + 1, 0))
+    {
+      re_dfastate_t **new_array;
+      Idx old_alloc = path->alloc;
+      Idx incr_alloc = last_str + mctx->max_mb_elem_len + 1;
+      Idx new_alloc;
+      if (BE (IDX_MAX - old_alloc < incr_alloc, 0))
+	return REG_ESPACE;
+      new_alloc = old_alloc + incr_alloc;
+      if (BE (SIZE_MAX / sizeof (re_dfastate_t *) < new_alloc, 0))
+	return REG_ESPACE;
+      new_array = re_realloc (path->array, re_dfastate_t *, new_alloc);
+      if (BE (new_array == NULL, 0))
+	return REG_ESPACE;
+      path->array = new_array;
+      path->alloc = new_alloc;
+      memset (new_array + old_alloc, '\0',
+	      sizeof (re_dfastate_t *) * (path->alloc - old_alloc));
+    }
+
+  str_idx = path->next_idx ? path->next_idx : top_str;
+
+  /* Temporary modify MCTX.  */
+  backup_state_log = mctx->state_log;
+  backup_cur_idx = mctx->input.cur_idx;
+  mctx->state_log = path->array;
+  mctx->input.cur_idx = str_idx;
+
+  /* Setup initial node set.  */
+  context = re_string_context_at (&mctx->input, str_idx - 1, mctx->eflags);
+  if (str_idx == top_str)
+    {
+      err = re_node_set_init_1 (&next_nodes, top_node);
+      if (BE (err != REG_NOERROR, 0))
+	return err;
+      err = check_arrival_expand_ecl (dfa, &next_nodes, subexp_num, type);
+      if (BE (err != REG_NOERROR, 0))
+	{
+	  re_node_set_free (&next_nodes);
+	  return err;
+	}
+    }
+  else
+    {
+      cur_state = mctx->state_log[str_idx];
+      if (cur_state && cur_state->has_backref)
+	{
+	  err = re_node_set_init_copy (&next_nodes, &cur_state->nodes);
+	  if (BE (err != REG_NOERROR, 0))
+	    return err;
+	}
+      else
+	re_node_set_init_empty (&next_nodes);
+    }
+  if (str_idx == top_str || (cur_state && cur_state->has_backref))
+    {
+      if (next_nodes.nelem)
+	{
+	  err = expand_bkref_cache (mctx, &next_nodes, str_idx,
+				    subexp_num, type);
+	  if (BE (err != REG_NOERROR, 0))
+	    {
+	      re_node_set_free (&next_nodes);
+	      return err;
+	    }
+	}
+      cur_state = re_acquire_state_context (&err, dfa, &next_nodes, context);
+      if (BE (cur_state == NULL && err != REG_NOERROR, 0))
+	{
+	  re_node_set_free (&next_nodes);
+	  return err;
+	}
+      mctx->state_log[str_idx] = cur_state;
+    }
+
+  for (null_cnt = 0; str_idx < last_str && null_cnt <= mctx->max_mb_elem_len;)
+    {
+      re_node_set_empty (&next_nodes);
+      if (mctx->state_log[str_idx + 1])
+	{
+	  err = re_node_set_merge (&next_nodes,
+				   &mctx->state_log[str_idx + 1]->nodes);
+	  if (BE (err != REG_NOERROR, 0))
+	    {
+	      re_node_set_free (&next_nodes);
+	      return err;
+	    }
+	}
+      if (cur_state)
+	{
+	  err = check_arrival_add_next_nodes (mctx, str_idx,
+					      &cur_state->non_eps_nodes,
+					      &next_nodes);
+	  if (BE (err != REG_NOERROR, 0))
+	    {
+	      re_node_set_free (&next_nodes);
+	      return err;
+	    }
+	}
+      ++str_idx;
+      if (next_nodes.nelem)
+	{
+	  err = check_arrival_expand_ecl (dfa, &next_nodes, subexp_num, type);
+	  if (BE (err != REG_NOERROR, 0))
+	    {
+	      re_node_set_free (&next_nodes);
+	      return err;
+	    }
+	  err = expand_bkref_cache (mctx, &next_nodes, str_idx,
+				    subexp_num, type);
+	  if (BE (err != REG_NOERROR, 0))
+	    {
+	      re_node_set_free (&next_nodes);
+	      return err;
+	    }
+	}
+      context = re_string_context_at (&mctx->input, str_idx - 1, mctx->eflags);
+      cur_state = re_acquire_state_context (&err, dfa, &next_nodes, context);
+      if (BE (cur_state == NULL && err != REG_NOERROR, 0))
+	{
+	  re_node_set_free (&next_nodes);
+	  return err;
+	}
+      mctx->state_log[str_idx] = cur_state;
+      null_cnt = cur_state == NULL ? null_cnt + 1 : 0;
+    }
+  re_node_set_free (&next_nodes);
+  cur_nodes = (mctx->state_log[last_str] == NULL ? NULL
+	       : &mctx->state_log[last_str]->nodes);
+  path->next_idx = str_idx;
+
+  /* Fix MCTX.  */
+  mctx->state_log = backup_state_log;
+  mctx->input.cur_idx = backup_cur_idx;
+
+  /* Then check the current node set has the node LAST_NODE.  */
+  if (cur_nodes != NULL && re_node_set_contains (cur_nodes, last_node))
+    return REG_NOERROR;
+
+  return REG_NOMATCH;
+}
+
+/* Helper functions for check_arrival.  */
+
+/* Calculate the destination nodes of CUR_NODES at STR_IDX, and append them
+   to NEXT_NODES.
+   TODO: This function is similar to the functions transit_state*(),
+	 however this function has many additional works.
+	 Can't we unify them?  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+check_arrival_add_next_nodes (re_match_context_t *mctx, Idx str_idx,
+			      re_node_set *cur_nodes, re_node_set *next_nodes)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  bool ok;
+  Idx cur_idx;
+#ifdef RE_ENABLE_I18N
+  reg_errcode_t err = REG_NOERROR;
+#endif
+  re_node_set union_set;
+  re_node_set_init_empty (&union_set);
+  for (cur_idx = 0; cur_idx < cur_nodes->nelem; ++cur_idx)
+    {
+      int naccepted = 0;
+      Idx cur_node = cur_nodes->elems[cur_idx];
+#ifdef DEBUG
+      re_token_type_t type = dfa->nodes[cur_node].type;
+      assert (!IS_EPSILON_NODE (type));
+#endif
+#ifdef RE_ENABLE_I18N
+      /* If the node may accept "multi byte".  */
+      if (dfa->nodes[cur_node].accept_mb)
+	{
+	  naccepted = check_node_accept_bytes (dfa, cur_node, &mctx->input,
+					       str_idx);
+	  if (naccepted > 1)
+	    {
+	      re_dfastate_t *dest_state;
+	      Idx next_node = dfa->nexts[cur_node];
+	      Idx next_idx = str_idx + naccepted;
+	      dest_state = mctx->state_log[next_idx];
+	      re_node_set_empty (&union_set);
+	      if (dest_state)
+		{
+		  err = re_node_set_merge (&union_set, &dest_state->nodes);
+		  if (BE (err != REG_NOERROR, 0))
+		    {
+		      re_node_set_free (&union_set);
+		      return err;
+		    }
+		}
+	      ok = re_node_set_insert (&union_set, next_node);
+	      if (BE (! ok, 0))
+		{
+		  re_node_set_free (&union_set);
+		  return REG_ESPACE;
+		}
+	      mctx->state_log[next_idx] = re_acquire_state (&err, dfa,
+							    &union_set);
+	      if (BE (mctx->state_log[next_idx] == NULL
+		      && err != REG_NOERROR, 0))
+		{
+		  re_node_set_free (&union_set);
+		  return err;
+		}
+	    }
+	}
+#endif /* RE_ENABLE_I18N */
+      if (naccepted
+	  || check_node_accept (mctx, dfa->nodes + cur_node, str_idx))
+	{
+	  ok = re_node_set_insert (next_nodes, dfa->nexts[cur_node]);
+	  if (BE (! ok, 0))
+	    {
+	      re_node_set_free (&union_set);
+	      return REG_ESPACE;
+	    }
+	}
+    }
+  re_node_set_free (&union_set);
+  return REG_NOERROR;
+}
+
+/* For all the nodes in CUR_NODES, add the epsilon closures of them to
+   CUR_NODES, however exclude the nodes which are:
+    - inside the sub expression whose number is EX_SUBEXP, if FL_OPEN.
+    - out of the sub expression whose number is EX_SUBEXP, if !FL_OPEN.
+*/
+
+static reg_errcode_t
+check_arrival_expand_ecl (const re_dfa_t *dfa, re_node_set *cur_nodes,
+			  Idx ex_subexp, int type)
+{
+  reg_errcode_t err;
+  Idx idx, outside_node;
+  re_node_set new_nodes;
+#ifdef DEBUG
+  assert (cur_nodes->nelem);
+#endif
+  err = re_node_set_alloc (&new_nodes, cur_nodes->nelem);
+  if (BE (err != REG_NOERROR, 0))
+    return err;
+  /* Create a new node set NEW_NODES with the nodes which are epsilon
+     closures of the node in CUR_NODES.  */
+
+  for (idx = 0; idx < cur_nodes->nelem; ++idx)
+    {
+      Idx cur_node = cur_nodes->elems[idx];
+      const re_node_set *eclosure = dfa->eclosures + cur_node;
+      outside_node = find_subexp_node (dfa, eclosure, ex_subexp, type);
+      if (outside_node == -1)
+	{
+	  /* There are no problematic nodes, just merge them.  */
+	  err = re_node_set_merge (&new_nodes, eclosure);
+	  if (BE (err != REG_NOERROR, 0))
+	    {
+	      re_node_set_free (&new_nodes);
+	      return err;
+	    }
+	}
+      else
+	{
+	  /* There are problematic nodes, re-calculate incrementally.  */
+	  err = check_arrival_expand_ecl_sub (dfa, &new_nodes, cur_node,
+					      ex_subexp, type);
+	  if (BE (err != REG_NOERROR, 0))
+	    {
+	      re_node_set_free (&new_nodes);
+	      return err;
+	    }
+	}
+    }
+  re_node_set_free (cur_nodes);
+  *cur_nodes = new_nodes;
+  return REG_NOERROR;
+}
+
+/* Helper function for check_arrival_expand_ecl.
+   Check incrementally the epsilon closure of TARGET, and if it isn't
+   problematic append it to DST_NODES.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+check_arrival_expand_ecl_sub (const re_dfa_t *dfa, re_node_set *dst_nodes,
+			      Idx target, Idx ex_subexp, int type)
+{
+  Idx cur_node;
+  for (cur_node = target; !re_node_set_contains (dst_nodes, cur_node);)
+    {
+      bool ok;
+
+      if (dfa->nodes[cur_node].type == type
+	  && dfa->nodes[cur_node].opr.idx == ex_subexp)
+	{
+	  if (type == OP_CLOSE_SUBEXP)
+	    {
+	      ok = re_node_set_insert (dst_nodes, cur_node);
+	      if (BE (! ok, 0))
+		return REG_ESPACE;
+	    }
+	  break;
+	}
+      ok = re_node_set_insert (dst_nodes, cur_node);
+      if (BE (! ok, 0))
+	return REG_ESPACE;
+      if (dfa->edests[cur_node].nelem == 0)
+	break;
+      if (dfa->edests[cur_node].nelem == 2)
+	{
+	  reg_errcode_t err;
+	  err = check_arrival_expand_ecl_sub (dfa, dst_nodes,
+					      dfa->edests[cur_node].elems[1],
+					      ex_subexp, type);
+	  if (BE (err != REG_NOERROR, 0))
+	    return err;
+	}
+      cur_node = dfa->edests[cur_node].elems[0];
+    }
+  return REG_NOERROR;
+}
+
+
+/* For all the back references in the current state, calculate the
+   destination of the back references by the appropriate entry
+   in MCTX->BKREF_ENTS.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+expand_bkref_cache (re_match_context_t *mctx, re_node_set *cur_nodes,
+		    Idx cur_str, Idx subexp_num, int type)
+{
+  const re_dfa_t *const dfa = mctx->dfa;
+  reg_errcode_t err;
+  Idx cache_idx_start = search_cur_bkref_entry (mctx, cur_str);
+  struct re_backref_cache_entry *ent;
+
+  if (cache_idx_start == -1)
+    return REG_NOERROR;
+
+ restart:
+  ent = mctx->bkref_ents + cache_idx_start;
+  do
+    {
+      Idx to_idx, next_node;
+
+      /* Is this entry ENT is appropriate?  */
+      if (!re_node_set_contains (cur_nodes, ent->node))
+	continue; /* No.  */
+
+      to_idx = cur_str + ent->subexp_to - ent->subexp_from;
+      /* Calculate the destination of the back reference, and append it
+	 to MCTX->STATE_LOG.  */
+      if (to_idx == cur_str)
+	{
+	  /* The backreference did epsilon transit, we must re-check all the
+	     node in the current state.  */
+	  re_node_set new_dests;
+	  reg_errcode_t err2, err3;
+	  next_node = dfa->edests[ent->node].elems[0];
+	  if (re_node_set_contains (cur_nodes, next_node))
+	    continue;
+	  err = re_node_set_init_1 (&new_dests, next_node);
+	  err2 = check_arrival_expand_ecl (dfa, &new_dests, subexp_num, type);
+	  err3 = re_node_set_merge (cur_nodes, &new_dests);
+	  re_node_set_free (&new_dests);
+	  if (BE (err != REG_NOERROR || err2 != REG_NOERROR
+		  || err3 != REG_NOERROR, 0))
+	    {
+	      err = (err != REG_NOERROR ? err
+		     : (err2 != REG_NOERROR ? err2 : err3));
+	      return err;
+	    }
+	  /* TODO: It is still inefficient...  */
+	  goto restart;
+	}
+      else
+	{
+	  re_node_set union_set;
+	  next_node = dfa->nexts[ent->node];
+	  if (mctx->state_log[to_idx])
+	    {
+	      bool ok;
+	      if (re_node_set_contains (&mctx->state_log[to_idx]->nodes,
+					next_node))
+		continue;
+	      err = re_node_set_init_copy (&union_set,
+					   &mctx->state_log[to_idx]->nodes);
+	      ok = re_node_set_insert (&union_set, next_node);
+	      if (BE (err != REG_NOERROR || ! ok, 0))
+		{
+		  re_node_set_free (&union_set);
+		  err = err != REG_NOERROR ? err : REG_ESPACE;
+		  return err;
+		}
+	    }
+	  else
+	    {
+	      err = re_node_set_init_1 (&union_set, next_node);
+	      if (BE (err != REG_NOERROR, 0))
+		return err;
+	    }
+	  mctx->state_log[to_idx] = re_acquire_state (&err, dfa, &union_set);
+	  re_node_set_free (&union_set);
+	  if (BE (mctx->state_log[to_idx] == NULL
+		  && err != REG_NOERROR, 0))
+	    return err;
+	}
+    }
+  while (ent++->more);
+  return REG_NOERROR;
+}
+
+/* Build transition table for the state.
+   Return true if successful.  */
+
+static bool
+build_trtable (const re_dfa_t *dfa, re_dfastate_t *state)
+{
+  reg_errcode_t err;
+  Idx i, j;
+  int ch;
+  bool need_word_trtable = false;
+  bitset_word_t elem, mask;
+  bool dests_node_malloced = false;
+  bool dest_states_malloced = false;
+  Idx ndests; /* Number of the destination states from 'state'.  */
+  re_dfastate_t **trtable;
+  re_dfastate_t **dest_states = NULL, **dest_states_word, **dest_states_nl;
+  re_node_set follows, *dests_node;
+  bitset_t *dests_ch;
+  bitset_t acceptable;
+
+  struct dests_alloc
+  {
+    re_node_set dests_node[SBC_MAX];
+    bitset_t dests_ch[SBC_MAX];
+  } *dests_alloc;
+
+  /* We build DFA states which corresponds to the destination nodes
+     from 'state'.  'dests_node[i]' represents the nodes which i-th
+     destination state contains, and 'dests_ch[i]' represents the
+     characters which i-th destination state accepts.  */
+  if (__libc_use_alloca (sizeof (struct dests_alloc)))
+    dests_alloc = (struct dests_alloc *) alloca (sizeof (struct dests_alloc));
+  else
+    {
+      dests_alloc = re_malloc (struct dests_alloc, 1);
+      if (BE (dests_alloc == NULL, 0))
+	return false;
+      dests_node_malloced = true;
+    }
+  dests_node = dests_alloc->dests_node;
+  dests_ch = dests_alloc->dests_ch;
+
+  /* Initialize transition table.  */
+  state->word_trtable = state->trtable = NULL;
+
+  /* At first, group all nodes belonging to 'state' into several
+     destinations.  */
+  ndests = group_nodes_into_DFAstates (dfa, state, dests_node, dests_ch);
+  if (BE (ndests <= 0, 0))
+    {
+      if (dests_node_malloced)
+	re_free (dests_alloc);
+      /* Return false in case of an error, true otherwise.  */
+      if (ndests == 0)
+	{
+	  state->trtable = (re_dfastate_t **)
+	    calloc (sizeof (re_dfastate_t *), SBC_MAX);
+          if (BE (state->trtable == NULL, 0))
+            return false;
+	  return true;
+	}
+      return false;
+    }
+
+  err = re_node_set_alloc (&follows, ndests + 1);
+  if (BE (err != REG_NOERROR, 0))
+    goto out_free;
+
+  /* Avoid arithmetic overflow in size calculation.  */
+  if (BE ((((SIZE_MAX - (sizeof (re_node_set) + sizeof (bitset_t)) * SBC_MAX)
+	    / (3 * sizeof (re_dfastate_t *)))
+	   < ndests),
+	  0))
+    goto out_free;
+
+  if (__libc_use_alloca ((sizeof (re_node_set) + sizeof (bitset_t)) * SBC_MAX
+			 + ndests * 3 * sizeof (re_dfastate_t *)))
+    dest_states = (re_dfastate_t **)
+      alloca (ndests * 3 * sizeof (re_dfastate_t *));
+  else
+    {
+      dest_states = re_malloc (re_dfastate_t *, ndests * 3);
+      if (BE (dest_states == NULL, 0))
+	{
+out_free:
+	  if (dest_states_malloced)
+	    re_free (dest_states);
+	  re_node_set_free (&follows);
+	  for (i = 0; i < ndests; ++i)
+	    re_node_set_free (dests_node + i);
+	  if (dests_node_malloced)
+	    re_free (dests_alloc);
+	  return false;
+	}
+      dest_states_malloced = true;
+    }
+  dest_states_word = dest_states + ndests;
+  dest_states_nl = dest_states_word + ndests;
+  bitset_empty (acceptable);
+
+  /* Then build the states for all destinations.  */
+  for (i = 0; i < ndests; ++i)
+    {
+      Idx next_node;
+      re_node_set_empty (&follows);
+      /* Merge the follows of this destination states.  */
+      for (j = 0; j < dests_node[i].nelem; ++j)
+	{
+	  next_node = dfa->nexts[dests_node[i].elems[j]];
+	  if (next_node != -1)
+	    {
+	      err = re_node_set_merge (&follows, dfa->eclosures + next_node);
+	      if (BE (err != REG_NOERROR, 0))
+		goto out_free;
+	    }
+	}
+      dest_states[i] = re_acquire_state_context (&err, dfa, &follows, 0);
+      if (BE (dest_states[i] == NULL && err != REG_NOERROR, 0))
+	goto out_free;
+      /* If the new state has context constraint,
+	 build appropriate states for these contexts.  */
+      if (dest_states[i]->has_constraint)
+	{
+	  dest_states_word[i] = re_acquire_state_context (&err, dfa, &follows,
+							  CONTEXT_WORD);
+	  if (BE (dest_states_word[i] == NULL && err != REG_NOERROR, 0))
+	    goto out_free;
+
+	  if (dest_states[i] != dest_states_word[i] && dfa->mb_cur_max > 1)
+	    need_word_trtable = true;
+
+	  dest_states_nl[i] = re_acquire_state_context (&err, dfa, &follows,
+							CONTEXT_NEWLINE);
+	  if (BE (dest_states_nl[i] == NULL && err != REG_NOERROR, 0))
+	    goto out_free;
+	}
+      else
+	{
+	  dest_states_word[i] = dest_states[i];
+	  dest_states_nl[i] = dest_states[i];
+	}
+      bitset_merge (acceptable, dests_ch[i]);
+    }
+
+  if (!BE (need_word_trtable, 0))
+    {
+      /* We don't care about whether the following character is a word
+	 character, or we are in a single-byte character set so we can
+	 discern by looking at the character code: allocate a
+	 256-entry transition table.  */
+      trtable = state->trtable =
+	(re_dfastate_t **) calloc (sizeof (re_dfastate_t *), SBC_MAX);
+      if (BE (trtable == NULL, 0))
+	goto out_free;
+
+      /* For all characters ch...:  */
+      for (i = 0; i < BITSET_WORDS; ++i)
+	for (ch = i * BITSET_WORD_BITS, elem = acceptable[i], mask = 1;
+	     elem;
+	     mask <<= 1, elem >>= 1, ++ch)
+	  if (BE (elem & 1, 0))
+	    {
+	      /* There must be exactly one destination which accepts
+		 character ch.  See group_nodes_into_DFAstates.  */
+	      for (j = 0; (dests_ch[j][i] & mask) == 0; ++j)
+		;
+
+	      /* j-th destination accepts the word character ch.  */
+	      if (dfa->word_char[i] & mask)
+		trtable[ch] = dest_states_word[j];
+	      else
+		trtable[ch] = dest_states[j];
+	    }
+    }
+  else
+    {
+      /* We care about whether the following character is a word
+	 character, and we are in a multi-byte character set: discern
+	 by looking at the character code: build two 256-entry
+	 transition tables, one starting at trtable[0] and one
+	 starting at trtable[SBC_MAX].  */
+      trtable = state->word_trtable =
+	(re_dfastate_t **) calloc (sizeof (re_dfastate_t *), 2 * SBC_MAX);
+      if (BE (trtable == NULL, 0))
+	goto out_free;
+
+      /* For all characters ch...:  */
+      for (i = 0; i < BITSET_WORDS; ++i)
+	for (ch = i * BITSET_WORD_BITS, elem = acceptable[i], mask = 1;
+	     elem;
+	     mask <<= 1, elem >>= 1, ++ch)
+	  if (BE (elem & 1, 0))
+	    {
+	      /* There must be exactly one destination which accepts
+		 character ch.  See group_nodes_into_DFAstates.  */
+	      for (j = 0; (dests_ch[j][i] & mask) == 0; ++j)
+		;
+
+	      /* j-th destination accepts the word character ch.  */
+	      trtable[ch] = dest_states[j];
+	      trtable[ch + SBC_MAX] = dest_states_word[j];
+	    }
+    }
+
+  /* new line */
+  if (bitset_contain (acceptable, NEWLINE_CHAR))
+    {
+      /* The current state accepts newline character.  */
+      for (j = 0; j < ndests; ++j)
+	if (bitset_contain (dests_ch[j], NEWLINE_CHAR))
+	  {
+	    /* k-th destination accepts newline character.  */
+	    trtable[NEWLINE_CHAR] = dest_states_nl[j];
+	    if (need_word_trtable)
+	      trtable[NEWLINE_CHAR + SBC_MAX] = dest_states_nl[j];
+	    /* There must be only one destination which accepts
+	       newline.  See group_nodes_into_DFAstates.  */
+	    break;
+	  }
+    }
+
+  if (dest_states_malloced)
+    re_free (dest_states);
+
+  re_node_set_free (&follows);
+  for (i = 0; i < ndests; ++i)
+    re_node_set_free (dests_node + i);
+
+  if (dests_node_malloced)
+    re_free (dests_alloc);
+
+  return true;
+}
+
+/* Group all nodes belonging to STATE into several destinations.
+   Then for all destinations, set the nodes belonging to the destination
+   to DESTS_NODE[i] and set the characters accepted by the destination
+   to DEST_CH[i].  This function return the number of destinations.  */
+
+static Idx
+group_nodes_into_DFAstates (const re_dfa_t *dfa, const re_dfastate_t *state,
+			    re_node_set *dests_node, bitset_t *dests_ch)
+{
+  reg_errcode_t err;
+  bool ok;
+  Idx i, j, k;
+  Idx ndests; /* Number of the destinations from 'state'.  */
+  bitset_t accepts; /* Characters a node can accept.  */
+  const re_node_set *cur_nodes = &state->nodes;
+  bitset_empty (accepts);
+  ndests = 0;
+
+  /* For all the nodes belonging to 'state',  */
+  for (i = 0; i < cur_nodes->nelem; ++i)
+    {
+      re_token_t *node = &dfa->nodes[cur_nodes->elems[i]];
+      re_token_type_t type = node->type;
+      unsigned int constraint = node->constraint;
+
+      /* Enumerate all single byte character this node can accept.  */
+      if (type == CHARACTER)
+	bitset_set (accepts, node->opr.c);
+      else if (type == SIMPLE_BRACKET)
+	{
+	  bitset_merge (accepts, node->opr.sbcset);
+	}
+      else if (type == OP_PERIOD)
+	{
+#ifdef RE_ENABLE_I18N
+	  if (dfa->mb_cur_max > 1)
+	    bitset_merge (accepts, dfa->sb_char);
+	  else
+#endif
+	    bitset_set_all (accepts);
+	  if (!(dfa->syntax & RE_DOT_NEWLINE))
+	    bitset_clear (accepts, '\n');
+	  if (dfa->syntax & RE_DOT_NOT_NULL)
+	    bitset_clear (accepts, '\0');
+	}
+#ifdef RE_ENABLE_I18N
+      else if (type == OP_UTF8_PERIOD)
+	{
+	  if (ASCII_CHARS % BITSET_WORD_BITS == 0)
+	    memset (accepts, -1, ASCII_CHARS / CHAR_BIT);
+	  else
+	    bitset_merge (accepts, utf8_sb_map);
+	  if (!(dfa->syntax & RE_DOT_NEWLINE))
+	    bitset_clear (accepts, '\n');
+	  if (dfa->syntax & RE_DOT_NOT_NULL)
+	    bitset_clear (accepts, '\0');
+	}
+#endif
+      else
+	continue;
+
+      /* Check the 'accepts' and sift the characters which are not
+	 match it the context.  */
+      if (constraint)
+	{
+	  if (constraint & NEXT_NEWLINE_CONSTRAINT)
+	    {
+	      bool accepts_newline = bitset_contain (accepts, NEWLINE_CHAR);
+	      bitset_empty (accepts);
+	      if (accepts_newline)
+		bitset_set (accepts, NEWLINE_CHAR);
+	      else
+		continue;
+	    }
+	  if (constraint & NEXT_ENDBUF_CONSTRAINT)
+	    {
+	      bitset_empty (accepts);
+	      continue;
+	    }
+
+	  if (constraint & NEXT_WORD_CONSTRAINT)
+	    {
+	      bitset_word_t any_set = 0;
+	      if (type == CHARACTER && !node->word_char)
+		{
+		  bitset_empty (accepts);
+		  continue;
+		}
+#ifdef RE_ENABLE_I18N
+	      if (dfa->mb_cur_max > 1)
+		for (j = 0; j < BITSET_WORDS; ++j)
+		  any_set |= (accepts[j] &= (dfa->word_char[j] | ~dfa->sb_char[j]));
+	      else
+#endif
+		for (j = 0; j < BITSET_WORDS; ++j)
+		  any_set |= (accepts[j] &= dfa->word_char[j]);
+	      if (!any_set)
+		continue;
+	    }
+	  if (constraint & NEXT_NOTWORD_CONSTRAINT)
+	    {
+	      bitset_word_t any_set = 0;
+	      if (type == CHARACTER && node->word_char)
+		{
+		  bitset_empty (accepts);
+		  continue;
+		}
+#ifdef RE_ENABLE_I18N
+	      if (dfa->mb_cur_max > 1)
+		for (j = 0; j < BITSET_WORDS; ++j)
+		  any_set |= (accepts[j] &= ~(dfa->word_char[j] & dfa->sb_char[j]));
+	      else
+#endif
+		for (j = 0; j < BITSET_WORDS; ++j)
+		  any_set |= (accepts[j] &= ~dfa->word_char[j]);
+	      if (!any_set)
+		continue;
+	    }
+	}
+
+      /* Then divide 'accepts' into DFA states, or create a new
+	 state.  Above, we make sure that accepts is not empty.  */
+      for (j = 0; j < ndests; ++j)
+	{
+	  bitset_t intersec; /* Intersection sets, see below.  */
+	  bitset_t remains;
+	  /* Flags, see below.  */
+	  bitset_word_t has_intersec, not_subset, not_consumed;
+
+	  /* Optimization, skip if this state doesn't accept the character.  */
+	  if (type == CHARACTER && !bitset_contain (dests_ch[j], node->opr.c))
+	    continue;
+
+	  /* Enumerate the intersection set of this state and 'accepts'.  */
+	  has_intersec = 0;
+	  for (k = 0; k < BITSET_WORDS; ++k)
+	    has_intersec |= intersec[k] = accepts[k] & dests_ch[j][k];
+	  /* And skip if the intersection set is empty.  */
+	  if (!has_intersec)
+	    continue;
+
+	  /* Then check if this state is a subset of 'accepts'.  */
+	  not_subset = not_consumed = 0;
+	  for (k = 0; k < BITSET_WORDS; ++k)
+	    {
+	      not_subset |= remains[k] = ~accepts[k] & dests_ch[j][k];
+	      not_consumed |= accepts[k] = accepts[k] & ~dests_ch[j][k];
+	    }
+
+	  /* If this state isn't a subset of 'accepts', create a
+	     new group state, which has the 'remains'. */
+	  if (not_subset)
+	    {
+	      bitset_copy (dests_ch[ndests], remains);
+	      bitset_copy (dests_ch[j], intersec);
+	      err = re_node_set_init_copy (dests_node + ndests, &dests_node[j]);
+	      if (BE (err != REG_NOERROR, 0))
+		goto error_return;
+	      ++ndests;
+	    }
+
+	  /* Put the position in the current group. */
+	  ok = re_node_set_insert (&dests_node[j], cur_nodes->elems[i]);
+	  if (BE (! ok, 0))
+	    goto error_return;
+
+	  /* If all characters are consumed, go to next node. */
+	  if (!not_consumed)
+	    break;
+	}
+      /* Some characters remain, create a new group. */
+      if (j == ndests)
+	{
+	  bitset_copy (dests_ch[ndests], accepts);
+	  err = re_node_set_init_1 (dests_node + ndests, cur_nodes->elems[i]);
+	  if (BE (err != REG_NOERROR, 0))
+	    goto error_return;
+	  ++ndests;
+	  bitset_empty (accepts);
+	}
+    }
+  return ndests;
+ error_return:
+  for (j = 0; j < ndests; ++j)
+    re_node_set_free (dests_node + j);
+  return -1;
+}
+
+#ifdef RE_ENABLE_I18N
+/* Check how many bytes the node 'dfa->nodes[node_idx]' accepts.
+   Return the number of the bytes the node accepts.
+   STR_IDX is the current index of the input string.
+
+   This function handles the nodes which can accept one character, or
+   one collating element like '.', '[a-z]', opposite to the other nodes
+   can only accept one byte.  */
+
+# ifdef _LIBC
+#  include <locale/weight.h>
+# endif
+
+static int
+check_node_accept_bytes (const re_dfa_t *dfa, Idx node_idx,
+			 const re_string_t *input, Idx str_idx)
+{
+  const re_token_t *node = dfa->nodes + node_idx;
+  int char_len, elem_len;
+  Idx i;
+
+  if (BE (node->type == OP_UTF8_PERIOD, 0))
+    {
+      unsigned char c = re_string_byte_at (input, str_idx), d;
+      if (BE (c < 0xc2, 1))
+	return 0;
+
+      if (str_idx + 2 > input->len)
+	return 0;
+
+      d = re_string_byte_at (input, str_idx + 1);
+      if (c < 0xe0)
+	return (d < 0x80 || d > 0xbf) ? 0 : 2;
+      else if (c < 0xf0)
+	{
+	  char_len = 3;
+	  if (c == 0xe0 && d < 0xa0)
+	    return 0;
+	}
+      else if (c < 0xf8)
+	{
+	  char_len = 4;
+	  if (c == 0xf0 && d < 0x90)
+	    return 0;
+	}
+      else if (c < 0xfc)
+	{
+	  char_len = 5;
+	  if (c == 0xf8 && d < 0x88)
+	    return 0;
+	}
+      else if (c < 0xfe)
+	{
+	  char_len = 6;
+	  if (c == 0xfc && d < 0x84)
+	    return 0;
+	}
+      else
+	return 0;
+
+      if (str_idx + char_len > input->len)
+	return 0;
+
+      for (i = 1; i < char_len; ++i)
+	{
+	  d = re_string_byte_at (input, str_idx + i);
+	  if (d < 0x80 || d > 0xbf)
+	    return 0;
+	}
+      return char_len;
+    }
+
+  char_len = re_string_char_size_at (input, str_idx);
+  if (node->type == OP_PERIOD)
+    {
+      if (char_len <= 1)
+	return 0;
+      /* FIXME: I don't think this if is needed, as both '\n'
+	 and '\0' are char_len == 1.  */
+      /* '.' accepts any one character except the following two cases.  */
+      if ((!(dfa->syntax & RE_DOT_NEWLINE) &&
+	   re_string_byte_at (input, str_idx) == '\n') ||
+	  ((dfa->syntax & RE_DOT_NOT_NULL) &&
+	   re_string_byte_at (input, str_idx) == '\0'))
+	return 0;
+      return char_len;
+    }
+
+  elem_len = re_string_elem_size_at (input, str_idx);
+  if ((elem_len <= 1 && char_len <= 1) || char_len == 0)
+    return 0;
+
+  if (node->type == COMPLEX_BRACKET)
+    {
+      const re_charset_t *cset = node->opr.mbcset;
+# ifdef _LIBC
+      const unsigned char *pin
+	= ((const unsigned char *) re_string_get_buffer (input) + str_idx);
+      Idx j;
+      uint32_t nrules;
+# endif /* _LIBC */
+      int match_len = 0;
+      wchar_t wc = ((cset->nranges || cset->nchar_classes || cset->nmbchars)
+		    ? re_string_wchar_at (input, str_idx) : 0);
+
+      /* match with multibyte character?  */
+      for (i = 0; i < cset->nmbchars; ++i)
+	if (wc == cset->mbchars[i])
+	  {
+	    match_len = char_len;
+	    goto check_node_accept_bytes_match;
+	  }
+      /* match with character_class?  */
+      for (i = 0; i < cset->nchar_classes; ++i)
+	{
+	  wctype_t wt = cset->char_classes[i];
+	  if (__iswctype (wc, wt))
+	    {
+	      match_len = char_len;
+	      goto check_node_accept_bytes_match;
+	    }
+	}
+
+# ifdef _LIBC
+      nrules = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES);
+      if (nrules != 0)
+	{
+	  unsigned int in_collseq = 0;
+	  const int32_t *table, *indirect;
+	  const unsigned char *weights, *extra;
+	  const char *collseqwc;
+
+	  /* match with collating_symbol?  */
+	  if (cset->ncoll_syms)
+	    extra = (const unsigned char *)
+	      _NL_CURRENT (LC_COLLATE, _NL_COLLATE_SYMB_EXTRAMB);
+	  for (i = 0; i < cset->ncoll_syms; ++i)
+	    {
+	      const unsigned char *coll_sym = extra + cset->coll_syms[i];
+	      /* Compare the length of input collating element and
+		 the length of current collating element.  */
+	      if (*coll_sym != elem_len)
+		continue;
+	      /* Compare each bytes.  */
+	      for (j = 0; j < *coll_sym; j++)
+		if (pin[j] != coll_sym[1 + j])
+		  break;
+	      if (j == *coll_sym)
+		{
+		  /* Match if every bytes is equal.  */
+		  match_len = j;
+		  goto check_node_accept_bytes_match;
+		}
+	    }
+
+	  if (cset->nranges)
+	    {
+	      if (elem_len <= char_len)
+		{
+		  collseqwc = _NL_CURRENT (LC_COLLATE, _NL_COLLATE_COLLSEQWC);
+		  in_collseq = __collseq_table_lookup (collseqwc, wc);
+		}
+	      else
+		in_collseq = find_collation_sequence_value (pin, elem_len);
+	    }
+	  /* match with range expression?  */
+	  /* FIXME: Implement rational ranges here, too.  */
+	  for (i = 0; i < cset->nranges; ++i)
+	    if (cset->range_starts[i] <= in_collseq
+		&& in_collseq <= cset->range_ends[i])
+	      {
+		match_len = elem_len;
+		goto check_node_accept_bytes_match;
+	      }
+
+	  /* match with equivalence_class?  */
+	  if (cset->nequiv_classes)
+	    {
+	      const unsigned char *cp = pin;
+	      table = (const int32_t *)
+		_NL_CURRENT (LC_COLLATE, _NL_COLLATE_TABLEMB);
+	      weights = (const unsigned char *)
+		_NL_CURRENT (LC_COLLATE, _NL_COLLATE_WEIGHTMB);
+	      extra = (const unsigned char *)
+		_NL_CURRENT (LC_COLLATE, _NL_COLLATE_EXTRAMB);
+	      indirect = (const int32_t *)
+		_NL_CURRENT (LC_COLLATE, _NL_COLLATE_INDIRECTMB);
+	      int32_t idx = findidx (table, indirect, extra, &cp, elem_len);
+	      int32_t rule = idx >> 24;
+	      idx &= 0xffffff;
+	      if (idx > 0)
+		{
+		  size_t weight_len = weights[idx];
+		  for (i = 0; i < cset->nequiv_classes; ++i)
+		    {
+		      int32_t equiv_class_idx = cset->equiv_classes[i];
+		      int32_t equiv_class_rule = equiv_class_idx >> 24;
+		      equiv_class_idx &= 0xffffff;
+		      if (weights[equiv_class_idx] == weight_len
+			  && equiv_class_rule == rule
+			  && memcmp (weights + idx + 1,
+				     weights + equiv_class_idx + 1,
+				     weight_len) == 0)
+			{
+			  match_len = elem_len;
+			  goto check_node_accept_bytes_match;
+			}
+		    }
+		}
+	    }
+	}
+      else
+# endif /* _LIBC */
+	{
+	  /* match with range expression?  */
+	  for (i = 0; i < cset->nranges; ++i)
+	    {
+	      if (cset->range_starts[i] <= wc && wc <= cset->range_ends[i])
+		{
+		  match_len = char_len;
+		  goto check_node_accept_bytes_match;
+		}
+	    }
+	}
+    check_node_accept_bytes_match:
+      if (!cset->non_match)
+	return match_len;
+      else
+	{
+	  if (match_len > 0)
+	    return 0;
+	  else
+	    return (elem_len > char_len) ? elem_len : char_len;
+	}
+    }
+  return 0;
+}
+
+# ifdef _LIBC
+static unsigned int
+find_collation_sequence_value (const unsigned char *mbs, size_t mbs_len)
+{
+  uint32_t nrules = _NL_CURRENT_WORD (LC_COLLATE, _NL_COLLATE_NRULES);
+  if (nrules == 0)
+    {
+      if (mbs_len == 1)
+	{
+	  /* No valid character.  Match it as a single byte character.  */
+	  const unsigned char *collseq = (const unsigned char *)
+	    _NL_CURRENT (LC_COLLATE, _NL_COLLATE_COLLSEQMB);
+	  return collseq[mbs[0]];
+	}
+      return UINT_MAX;
+    }
+  else
+    {
+      int32_t idx;
+      const unsigned char *extra = (const unsigned char *)
+	_NL_CURRENT (LC_COLLATE, _NL_COLLATE_SYMB_EXTRAMB);
+      int32_t extrasize = (const unsigned char *)
+	_NL_CURRENT (LC_COLLATE, _NL_COLLATE_SYMB_EXTRAMB + 1) - extra;
+
+      for (idx = 0; idx < extrasize;)
+	{
+	  int mbs_cnt;
+	  bool found = false;
+	  int32_t elem_mbs_len;
+	  /* Skip the name of collating element name.  */
+	  idx = idx + extra[idx] + 1;
+	  elem_mbs_len = extra[idx++];
+	  if (mbs_len == elem_mbs_len)
+	    {
+	      for (mbs_cnt = 0; mbs_cnt < elem_mbs_len; ++mbs_cnt)
+		if (extra[idx + mbs_cnt] != mbs[mbs_cnt])
+		  break;
+	      if (mbs_cnt == elem_mbs_len)
+		/* Found the entry.  */
+		found = true;
+	    }
+	  /* Skip the byte sequence of the collating element.  */
+	  idx += elem_mbs_len;
+	  /* Adjust for the alignment.  */
+	  idx = (idx + 3) & ~3;
+	  /* Skip the collation sequence value.  */
+	  idx += sizeof (uint32_t);
+	  /* Skip the wide char sequence of the collating element.  */
+	  idx = idx + sizeof (uint32_t) * (*(int32_t *) (extra + idx) + 1);
+	  /* If we found the entry, return the sequence value.  */
+	  if (found)
+	    return *(uint32_t *) (extra + idx);
+	  /* Skip the collation sequence value.  */
+	  idx += sizeof (uint32_t);
+	}
+      return UINT_MAX;
+    }
+}
+# endif /* _LIBC */
+#endif /* RE_ENABLE_I18N */
+
+/* Check whether the node accepts the byte which is IDX-th
+   byte of the INPUT.  */
+
+static bool
+check_node_accept (const re_match_context_t *mctx, const re_token_t *node,
+		   Idx idx)
+{
+  unsigned char ch;
+  ch = re_string_byte_at (&mctx->input, idx);
+  switch (node->type)
+    {
+    case CHARACTER:
+      if (node->opr.c != ch)
+        return false;
+      break;
+
+    case SIMPLE_BRACKET:
+      if (!bitset_contain (node->opr.sbcset, ch))
+        return false;
+      break;
+
+#ifdef RE_ENABLE_I18N
+    case OP_UTF8_PERIOD:
+      if (ch >= ASCII_CHARS)
+        return false;
+      FALLTHROUGH;
+#endif
+    case OP_PERIOD:
+      if ((ch == '\n' && !(mctx->dfa->syntax & RE_DOT_NEWLINE))
+	  || (ch == '\0' && (mctx->dfa->syntax & RE_DOT_NOT_NULL)))
+	return false;
+      break;
+
+    default:
+      return false;
+    }
+
+  if (node->constraint)
+    {
+      /* The node has constraints.  Check whether the current context
+	 satisfies the constraints.  */
+      unsigned int context = re_string_context_at (&mctx->input, idx,
+						   mctx->eflags);
+      if (NOT_SATISFY_NEXT_CONSTRAINT (node->constraint, context))
+	return false;
+    }
+
+  return true;
+}
+
+/* Extend the buffers, if the buffers have run out.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+extend_buffers (re_match_context_t *mctx, int min_len)
+{
+  reg_errcode_t ret;
+  re_string_t *pstr = &mctx->input;
+
+  /* Avoid overflow.  */
+  if (BE (MIN (IDX_MAX, SIZE_MAX / sizeof (re_dfastate_t *)) / 2
+          <= pstr->bufs_len, 0))
+    return REG_ESPACE;
+
+  /* Double the lengths of the buffers, but allocate at least MIN_LEN.  */
+  ret = re_string_realloc_buffers (pstr,
+				   MAX (min_len,
+					MIN (pstr->len, pstr->bufs_len * 2)));
+  if (BE (ret != REG_NOERROR, 0))
+    return ret;
+
+  if (mctx->state_log != NULL)
+    {
+      /* And double the length of state_log.  */
+      /* XXX We have no indication of the size of this buffer.  If this
+	 allocation fail we have no indication that the state_log array
+	 does not have the right size.  */
+      re_dfastate_t **new_array = re_realloc (mctx->state_log, re_dfastate_t *,
+					      pstr->bufs_len + 1);
+      if (BE (new_array == NULL, 0))
+	return REG_ESPACE;
+      mctx->state_log = new_array;
+    }
+
+  /* Then reconstruct the buffers.  */
+  if (pstr->icase)
+    {
+#ifdef RE_ENABLE_I18N
+      if (pstr->mb_cur_max > 1)
+	{
+	  ret = build_wcs_upper_buffer (pstr);
+	  if (BE (ret != REG_NOERROR, 0))
+	    return ret;
+	}
+      else
+#endif /* RE_ENABLE_I18N  */
+	build_upper_buffer (pstr);
+    }
+  else
+    {
+#ifdef RE_ENABLE_I18N
+      if (pstr->mb_cur_max > 1)
+	build_wcs_buffer (pstr);
+      else
+#endif /* RE_ENABLE_I18N  */
+	{
+	  if (pstr->trans != NULL)
+	    re_string_translate_buffer (pstr);
+	}
+    }
+  return REG_NOERROR;
+}
+
+
+/* Functions for matching context.  */
+
+/* Initialize MCTX.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+match_ctx_init (re_match_context_t *mctx, int eflags, Idx n)
+{
+  mctx->eflags = eflags;
+  mctx->match_last = -1;
+  if (n > 0)
+    {
+      /* Avoid overflow.  */
+      size_t max_object_size =
+	MAX (sizeof (struct re_backref_cache_entry),
+	     sizeof (re_sub_match_top_t *));
+      if (BE (MIN (IDX_MAX, SIZE_MAX / max_object_size) < n, 0))
+	return REG_ESPACE;
+
+      mctx->bkref_ents = re_malloc (struct re_backref_cache_entry, n);
+      mctx->sub_tops = re_malloc (re_sub_match_top_t *, n);
+      if (BE (mctx->bkref_ents == NULL || mctx->sub_tops == NULL, 0))
+	return REG_ESPACE;
+    }
+  /* Already zero-ed by the caller.
+     else
+       mctx->bkref_ents = NULL;
+     mctx->nbkref_ents = 0;
+     mctx->nsub_tops = 0;  */
+  mctx->abkref_ents = n;
+  mctx->max_mb_elem_len = 1;
+  mctx->asub_tops = n;
+  return REG_NOERROR;
+}
+
+/* Clean the entries which depend on the current input in MCTX.
+   This function must be invoked when the matcher changes the start index
+   of the input, or changes the input string.  */
+
+static void
+match_ctx_clean (re_match_context_t *mctx)
+{
+  Idx st_idx;
+  for (st_idx = 0; st_idx < mctx->nsub_tops; ++st_idx)
+    {
+      Idx sl_idx;
+      re_sub_match_top_t *top = mctx->sub_tops[st_idx];
+      for (sl_idx = 0; sl_idx < top->nlasts; ++sl_idx)
+	{
+	  re_sub_match_last_t *last = top->lasts[sl_idx];
+	  re_free (last->path.array);
+	  re_free (last);
+	}
+      re_free (top->lasts);
+      if (top->path)
+	{
+	  re_free (top->path->array);
+	  re_free (top->path);
+	}
+      re_free (top);
+    }
+
+  mctx->nsub_tops = 0;
+  mctx->nbkref_ents = 0;
+}
+
+/* Free all the memory associated with MCTX.  */
+
+static void
+match_ctx_free (re_match_context_t *mctx)
+{
+  /* First, free all the memory associated with MCTX->SUB_TOPS.  */
+  match_ctx_clean (mctx);
+  re_free (mctx->sub_tops);
+  re_free (mctx->bkref_ents);
+}
+
+/* Add a new backreference entry to MCTX.
+   Note that we assume that caller never call this function with duplicate
+   entry, and call with STR_IDX which isn't smaller than any existing entry.
+*/
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+match_ctx_add_entry (re_match_context_t *mctx, Idx node, Idx str_idx, Idx from,
+		     Idx to)
+{
+  if (mctx->nbkref_ents >= mctx->abkref_ents)
+    {
+      struct re_backref_cache_entry* new_entry;
+      new_entry = re_realloc (mctx->bkref_ents, struct re_backref_cache_entry,
+			      mctx->abkref_ents * 2);
+      if (BE (new_entry == NULL, 0))
+	{
+	  re_free (mctx->bkref_ents);
+	  return REG_ESPACE;
+	}
+      mctx->bkref_ents = new_entry;
+      memset (mctx->bkref_ents + mctx->nbkref_ents, '\0',
+	      sizeof (struct re_backref_cache_entry) * mctx->abkref_ents);
+      mctx->abkref_ents *= 2;
+    }
+  if (mctx->nbkref_ents > 0
+      && mctx->bkref_ents[mctx->nbkref_ents - 1].str_idx == str_idx)
+    mctx->bkref_ents[mctx->nbkref_ents - 1].more = 1;
+
+  mctx->bkref_ents[mctx->nbkref_ents].node = node;
+  mctx->bkref_ents[mctx->nbkref_ents].str_idx = str_idx;
+  mctx->bkref_ents[mctx->nbkref_ents].subexp_from = from;
+  mctx->bkref_ents[mctx->nbkref_ents].subexp_to = to;
+
+  /* This is a cache that saves negative results of check_dst_limits_calc_pos.
+     If bit N is clear, means that this entry won't epsilon-transition to
+     an OP_OPEN_SUBEXP or OP_CLOSE_SUBEXP for the N+1-th subexpression.  If
+     it is set, check_dst_limits_calc_pos_1 will recurse and try to find one
+     such node.
+
+     A backreference does not epsilon-transition unless it is empty, so set
+     to all zeros if FROM != TO.  */
+  mctx->bkref_ents[mctx->nbkref_ents].eps_reachable_subexps_map
+    = (from == to ? -1 : 0);
+
+  mctx->bkref_ents[mctx->nbkref_ents++].more = 0;
+  if (mctx->max_mb_elem_len < to - from)
+    mctx->max_mb_elem_len = to - from;
+  return REG_NOERROR;
+}
+
+/* Return the first entry with the same str_idx, or -1 if none is
+   found.  Note that MCTX->BKREF_ENTS is already sorted by MCTX->STR_IDX.  */
+
+static Idx
+search_cur_bkref_entry (const re_match_context_t *mctx, Idx str_idx)
+{
+  Idx left, right, mid, last;
+  last = right = mctx->nbkref_ents;
+  for (left = 0; left < right;)
+    {
+      mid = (left + right) / 2;
+      if (mctx->bkref_ents[mid].str_idx < str_idx)
+	left = mid + 1;
+      else
+	right = mid;
+    }
+  if (left < last && mctx->bkref_ents[left].str_idx == str_idx)
+    return left;
+  else
+    return -1;
+}
+
+/* Register the node NODE, whose type is OP_OPEN_SUBEXP, and which matches
+   at STR_IDX.  */
+
+static reg_errcode_t
+__attribute_warn_unused_result__
+match_ctx_add_subtop (re_match_context_t *mctx, Idx node, Idx str_idx)
+{
+#ifdef DEBUG
+  assert (mctx->sub_tops != NULL);
+  assert (mctx->asub_tops > 0);
+#endif
+  if (BE (mctx->nsub_tops == mctx->asub_tops, 0))
+    {
+      Idx new_asub_tops = mctx->asub_tops * 2;
+      re_sub_match_top_t **new_array = re_realloc (mctx->sub_tops,
+						   re_sub_match_top_t *,
+						   new_asub_tops);
+      if (BE (new_array == NULL, 0))
+	return REG_ESPACE;
+      mctx->sub_tops = new_array;
+      mctx->asub_tops = new_asub_tops;
+    }
+  mctx->sub_tops[mctx->nsub_tops] = calloc (1, sizeof (re_sub_match_top_t));
+  if (BE (mctx->sub_tops[mctx->nsub_tops] == NULL, 0))
+    return REG_ESPACE;
+  mctx->sub_tops[mctx->nsub_tops]->node = node;
+  mctx->sub_tops[mctx->nsub_tops++]->str_idx = str_idx;
+  return REG_NOERROR;
+}
+
+/* Register the node NODE, whose type is OP_CLOSE_SUBEXP, and which matches
+   at STR_IDX, whose corresponding OP_OPEN_SUBEXP is SUB_TOP.  */
+
+static re_sub_match_last_t *
+match_ctx_add_sublast (re_sub_match_top_t *subtop, Idx node, Idx str_idx)
+{
+  re_sub_match_last_t *new_entry;
+  if (BE (subtop->nlasts == subtop->alasts, 0))
+    {
+      Idx new_alasts = 2 * subtop->alasts + 1;
+      re_sub_match_last_t **new_array = re_realloc (subtop->lasts,
+						    re_sub_match_last_t *,
+						    new_alasts);
+      if (BE (new_array == NULL, 0))
+	return NULL;
+      subtop->lasts = new_array;
+      subtop->alasts = new_alasts;
+    }
+  new_entry = calloc (1, sizeof (re_sub_match_last_t));
+  if (BE (new_entry != NULL, 1))
+    {
+      subtop->lasts[subtop->nlasts] = new_entry;
+      new_entry->node = node;
+      new_entry->str_idx = str_idx;
+      ++subtop->nlasts;
+    }
+  return new_entry;
+}
+
+static void
+sift_ctx_init (re_sift_context_t *sctx, re_dfastate_t **sifted_sts,
+	       re_dfastate_t **limited_sts, Idx last_node, Idx last_str_idx)
+{
+  sctx->sifted_states = sifted_sts;
+  sctx->limited_states = limited_sts;
+  sctx->last_node = last_node;
+  sctx->last_str_idx = last_str_idx;
+  re_node_set_init_empty (&sctx->limits);
+}
diff --git a/lib/streq.h b/lib/streq.h
new file mode 100644
index 0000000000..bde1b9562f
--- /dev/null
+++ b/lib/streq.h
@@ -0,0 +1,176 @@
+/* Optimized string comparison.
+   Copyright (C) 2001-2002, 2007, 2009-2018 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published
+   by the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <[email-masked]>.  */
+
+#ifndef _GL_STREQ_H
+#define _GL_STREQ_H
+
+#include <string.h>
+
+/* STREQ_OPT allows to optimize string comparison with a small literal string.
+     STREQ_OPT (s, "EUC-KR", 'E', 'U', 'C', '-', 'K', 'R', 0, 0, 0)
+   is semantically equivalent to
+     strcmp (s, "EUC-KR") == 0
+   just faster.  */
+
+/* Help GCC to generate good code for string comparisons with
+   immediate strings. */
+#if defined (__GNUC__) && defined (__OPTIMIZE__)
+
+static inline int
+streq9 (const char *s1, const char *s2)
+{
+  return strcmp (s1 + 9, s2 + 9) == 0;
+}
+
+static inline int
+streq8 (const char *s1, const char *s2, char s28)
+{
+  if (s1[8] == s28)
+    {
+      if (s28 == 0)
+        return 1;
+      else
+        return streq9 (s1, s2);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq7 (const char *s1, const char *s2, char s27, char s28)
+{
+  if (s1[7] == s27)
+    {
+      if (s27 == 0)
+        return 1;
+      else
+        return streq8 (s1, s2, s28);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq6 (const char *s1, const char *s2, char s26, char s27, char s28)
+{
+  if (s1[6] == s26)
+    {
+      if (s26 == 0)
+        return 1;
+      else
+        return streq7 (s1, s2, s27, s28);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq5 (const char *s1, const char *s2, char s25, char s26, char s27, char s28)
+{
+  if (s1[5] == s25)
+    {
+      if (s25 == 0)
+        return 1;
+      else
+        return streq6 (s1, s2, s26, s27, s28);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq4 (const char *s1, const char *s2, char s24, char s25, char s26, char s27, char s28)
+{
+  if (s1[4] == s24)
+    {
+      if (s24 == 0)
+        return 1;
+      else
+        return streq5 (s1, s2, s25, s26, s27, s28);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq3 (const char *s1, const char *s2, char s23, char s24, char s25, char s26, char s27, char s28)
+{
+  if (s1[3] == s23)
+    {
+      if (s23 == 0)
+        return 1;
+      else
+        return streq4 (s1, s2, s24, s25, s26, s27, s28);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq2 (const char *s1, const char *s2, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
+{
+  if (s1[2] == s22)
+    {
+      if (s22 == 0)
+        return 1;
+      else
+        return streq3 (s1, s2, s23, s24, s25, s26, s27, s28);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq1 (const char *s1, const char *s2, char s21, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
+{
+  if (s1[1] == s21)
+    {
+      if (s21 == 0)
+        return 1;
+      else
+        return streq2 (s1, s2, s22, s23, s24, s25, s26, s27, s28);
+    }
+  else
+    return 0;
+}
+
+static inline int
+streq0 (const char *s1, const char *s2, char s20, char s21, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
+{
+  if (s1[0] == s20)
+    {
+      if (s20 == 0)
+        return 1;
+      else
+        return streq1 (s1, s2, s21, s22, s23, s24, s25, s26, s27, s28);
+    }
+  else
+    return 0;
+}
+
+#define STREQ_OPT(s1,s2,s20,s21,s22,s23,s24,s25,s26,s27,s28) \
+  streq0 (s1, s2, s20, s21, s22, s23, s24, s25, s26, s27, s28)
+
+#else
+
+#define STREQ_OPT(s1,s2,s20,s21,s22,s23,s24,s25,s26,s27,s28) \
+  (strcmp (s1, s2) == 0)
+
+#endif
+
+#endif /* _GL_STREQ_H */
diff --git a/lib/wchar.in.h b/lib/wchar.in.h
new file mode 100644
index 0000000000..51a5dda17d
--- /dev/null
+++ b/lib/wchar.in.h
@@ -0,0 +1,1072 @@
+/* A substitute for ISO C99 <wchar.h>, for platforms that have issues.
+
+   Copyright (C) 2007-2018 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Eric Blake.  */
+
+/*
+ * ISO C 99 <wchar.h> for platforms that have issues.
+ * <http://www.opengroup.org/susv3xbd/wchar.h.html>
+ *
+ * For now, this just ensures proper prerequisite inclusion order and
+ * the declaration of wcwidth().
+ */
+
+#if __GNUC__ >= 3
+@PRAGMA_SYSTEM_HEADER@
+#endif
+@PRAGMA_COLUMNS@
+
+#if (((defined __need_mbstate_t || defined __need_wint_t)               \
+      && !defined __MINGW32__)                                          \
+     || (defined __hpux                                                 \
+         && ((defined _INTTYPES_INCLUDED && !defined strtoimax)         \
+             || defined _GL_JUST_INCLUDE_SYSTEM_WCHAR_H))               \
+     || (defined __MINGW32__ && defined __STRING_H_SOURCED__)           \
+     || defined _GL_ALREADY_INCLUDING_WCHAR_H)
+/* Special invocation convention:
+   - Inside glibc and uClibc header files, but not MinGW.
+   - On HP-UX 11.00 we have a sequence of nested includes
+     <wchar.h> -> <stdlib.h> -> <stdint.h>, and the latter includes <wchar.h>,
+     once indirectly <stdint.h> -> <sys/types.h> -> <inttypes.h> -> <wchar.h>
+     and once directly.  In both situations 'wint_t' is not yet defined,
+     therefore we cannot provide the function overrides; instead include only
+     the system's <wchar.h>.
+   - With MinGW 3.22, when <string.h> includes <wchar.h>, only some part of
+     <wchar.h> is actually processed, and that doesn't include 'mbstate_t'.
+   - On IRIX 6.5, similarly, we have an include <wchar.h> -> <wctype.h>, and
+     the latter includes <wchar.h>.  But here, we have no way to detect whether
+     <wctype.h> is completely included or is still being included.  */
+
+#@INCLUDE_NEXT@ @NEXT_WCHAR_H@
+
+#else
+/* Normal invocation convention.  */
+
+#ifndef _@GUARD_PREFIX@_WCHAR_H
+
+#define _GL_ALREADY_INCLUDING_WCHAR_H
+
+#if @HAVE_FEATURES_H@
+# include <features.h> /* for __GLIBC__ */
+#endif
+
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.
+   In some builds of uClibc, <wchar.h> is nonexistent and wchar_t is defined
+   by <stddef.h>.
+   But avoid namespace pollution on glibc systems.  */
+#if !(defined __GLIBC__ && !defined __UCLIBC__)
+# include <stddef.h>
+#endif
+#ifndef __GLIBC__
+# include <stdio.h>
+# include <time.h>
+#endif
+
+/* Include the original <wchar.h> if it exists.
+   Some builds of uClibc lack it.  */
+/* The include_next requires a split double-inclusion guard.  */
+#if @HAVE_WCHAR_H@
+# @INCLUDE_NEXT@ @NEXT_WCHAR_H@
+#endif
+
+#undef _GL_ALREADY_INCLUDING_WCHAR_H
+
+#ifndef _@GUARD_PREFIX@_WCHAR_H
+#define _@GUARD_PREFIX@_WCHAR_H
+
+/* The __attribute__ feature is available in gcc versions 2.5 and later.
+   The attribute __pure__ was added in gcc 2.96.  */
+#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 96)
+# define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
+#else
+# define _GL_ATTRIBUTE_PURE /* empty */
+#endif
+
+/* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
+
+/* The definition of _GL_ARG_NONNULL is copied here.  */
+
+/* The definition of _GL_WARN_ON_USE is copied here.  */
+
+
+/* Define wint_t and WEOF.  (Also done in wctype.in.h.)  */
+#if !@HAVE_WINT_T@ && !defined wint_t
+# define wint_t int
+# ifndef WEOF
+#  define WEOF -1
+# endif
+#else
+/* mingw and MSVC define wint_t as 'unsigned short' in <crtdefs.h> or
+   <stddef.h>.  This is too small: ISO C 99 section 7.24.1.(2) says that
+   wint_t must be "unchanged by default argument promotions".  Override it.  */
+# if @GNULIB_OVERRIDES_WINT_T@
+#  if !GNULIB_defined_wint_t
+#   if @HAVE_CRTDEFS_H@
+#    include <crtdefs.h>
+#   else
+#    include <stddef.h>
+#   endif
+typedef unsigned int rpl_wint_t;
+#   undef wint_t
+#   define wint_t rpl_wint_t
+#   define GNULIB_defined_wint_t 1
+#  endif
+# endif
+# ifndef WEOF
+#  define WEOF ((wint_t) -1)
+# endif
+#endif
+
+
+/* Override mbstate_t if it is too small.
+   On IRIX 6.5, sizeof (mbstate_t) == 1, which is not sufficient for
+   implementing mbrtowc for encodings like UTF-8.  */
+#if !(@HAVE_MBSINIT@ && @HAVE_MBRTOWC@) || @REPLACE_MBSTATE_T@
+# if !GNULIB_defined_mbstate_t
+typedef int rpl_mbstate_t;
+#  undef mbstate_t
+#  define mbstate_t rpl_mbstate_t
+#  define GNULIB_defined_mbstate_t 1
+# endif
+#endif
+
+
+/* Convert a single-byte character to a wide character.  */
+#if @GNULIB_BTOWC@
+# if @REPLACE_BTOWC@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef btowc
+#   define btowc rpl_btowc
+#  endif
+_GL_FUNCDECL_RPL (btowc, wint_t, (int c) _GL_ATTRIBUTE_PURE);
+_GL_CXXALIAS_RPL (btowc, wint_t, (int c));
+# else
+#  if !@HAVE_BTOWC@
+_GL_FUNCDECL_SYS (btowc, wint_t, (int c) _GL_ATTRIBUTE_PURE);
+#  endif
+_GL_CXXALIAS_SYS (btowc, wint_t, (int c));
+# endif
+_GL_CXXALIASWARN (btowc);
+#elif defined GNULIB_POSIXCHECK
+# undef btowc
+# if HAVE_RAW_DECL_BTOWC
+_GL_WARN_ON_USE (btowc, "btowc is unportable - "
+                 "use gnulib module btowc for portability");
+# endif
+#endif
+
+
+/* Convert a wide character to a single-byte character.  */
+#if @GNULIB_WCTOB@
+# if @REPLACE_WCTOB@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef wctob
+#   define wctob rpl_wctob
+#  endif
+_GL_FUNCDECL_RPL (wctob, int, (wint_t wc) _GL_ATTRIBUTE_PURE);
+_GL_CXXALIAS_RPL (wctob, int, (wint_t wc));
+# else
+#  if !defined wctob && !@HAVE_DECL_WCTOB@
+/* wctob is provided by gnulib, or wctob exists but is not declared.  */
+_GL_FUNCDECL_SYS (wctob, int, (wint_t wc) _GL_ATTRIBUTE_PURE);
+#  endif
+_GL_CXXALIAS_SYS (wctob, int, (wint_t wc));
+# endif
+_GL_CXXALIASWARN (wctob);
+#elif defined GNULIB_POSIXCHECK
+# undef wctob
+# if HAVE_RAW_DECL_WCTOB
+_GL_WARN_ON_USE (wctob, "wctob is unportable - "
+                 "use gnulib module wctob for portability");
+# endif
+#endif
+
+
+/* Test whether *PS is in the initial state.  */
+#if @GNULIB_MBSINIT@
+# if @REPLACE_MBSINIT@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef mbsinit
+#   define mbsinit rpl_mbsinit
+#  endif
+_GL_FUNCDECL_RPL (mbsinit, int, (const mbstate_t *ps));
+_GL_CXXALIAS_RPL (mbsinit, int, (const mbstate_t *ps));
+# else
+#  if !@HAVE_MBSINIT@
+_GL_FUNCDECL_SYS (mbsinit, int, (const mbstate_t *ps));
+#  endif
+_GL_CXXALIAS_SYS (mbsinit, int, (const mbstate_t *ps));
+# endif
+_GL_CXXALIASWARN (mbsinit);
+#elif defined GNULIB_POSIXCHECK
+# undef mbsinit
+# if HAVE_RAW_DECL_MBSINIT
+_GL_WARN_ON_USE (mbsinit, "mbsinit is unportable - "
+                 "use gnulib module mbsinit for portability");
+# endif
+#endif
+
+
+/* Convert a multibyte character to a wide character.  */
+#if @GNULIB_MBRTOWC@
+# if @REPLACE_MBRTOWC@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef mbrtowc
+#   define mbrtowc rpl_mbrtowc
+#  endif
+_GL_FUNCDECL_RPL (mbrtowc, size_t,
+                  (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps));
+_GL_CXXALIAS_RPL (mbrtowc, size_t,
+                  (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps));
+# else
+#  if !@HAVE_MBRTOWC@
+_GL_FUNCDECL_SYS (mbrtowc, size_t,
+                  (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps));
+#  endif
+_GL_CXXALIAS_SYS (mbrtowc, size_t,
+                  (wchar_t *pwc, const char *s, size_t n, mbstate_t *ps));
+# endif
+_GL_CXXALIASWARN (mbrtowc);
+#elif defined GNULIB_POSIXCHECK
+# undef mbrtowc
+# if HAVE_RAW_DECL_MBRTOWC
+_GL_WARN_ON_USE (mbrtowc, "mbrtowc is unportable - "
+                 "use gnulib module mbrtowc for portability");
+# endif
+#endif
+
+
+/* Recognize a multibyte character.  */
+#if @GNULIB_MBRLEN@
+# if @REPLACE_MBRLEN@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef mbrlen
+#   define mbrlen rpl_mbrlen
+#  endif
+_GL_FUNCDECL_RPL (mbrlen, size_t, (const char *s, size_t n, mbstate_t *ps));
+_GL_CXXALIAS_RPL (mbrlen, size_t, (const char *s, size_t n, mbstate_t *ps));
+# else
+#  if !@HAVE_MBRLEN@
+_GL_FUNCDECL_SYS (mbrlen, size_t, (const char *s, size_t n, mbstate_t *ps));
+#  endif
+_GL_CXXALIAS_SYS (mbrlen, size_t, (const char *s, size_t n, mbstate_t *ps));
+# endif
+_GL_CXXALIASWARN (mbrlen);
+#elif defined GNULIB_POSIXCHECK
+# undef mbrlen
+# if HAVE_RAW_DECL_MBRLEN
+_GL_WARN_ON_USE (mbrlen, "mbrlen is unportable - "
+                 "use gnulib module mbrlen for portability");
+# endif
+#endif
+
+
+/* Convert a string to a wide string.  */
+#if @GNULIB_MBSRTOWCS@
+# if @REPLACE_MBSRTOWCS@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef mbsrtowcs
+#   define mbsrtowcs rpl_mbsrtowcs
+#  endif
+_GL_FUNCDECL_RPL (mbsrtowcs, size_t,
+                  (wchar_t *dest, const char **srcp, size_t len, mbstate_t *ps)
+                  _GL_ARG_NONNULL ((2)));
+_GL_CXXALIAS_RPL (mbsrtowcs, size_t,
+                  (wchar_t *dest, const char **srcp, size_t len,
+                   mbstate_t *ps));
+# else
+#  if !@HAVE_MBSRTOWCS@
+_GL_FUNCDECL_SYS (mbsrtowcs, size_t,
+                  (wchar_t *dest, const char **srcp, size_t len, mbstate_t *ps)
+                  _GL_ARG_NONNULL ((2)));
+#  endif
+_GL_CXXALIAS_SYS (mbsrtowcs, size_t,
+                  (wchar_t *dest, const char **srcp, size_t len,
+                   mbstate_t *ps));
+# endif
+_GL_CXXALIASWARN (mbsrtowcs);
+#elif defined GNULIB_POSIXCHECK
+# undef mbsrtowcs
+# if HAVE_RAW_DECL_MBSRTOWCS
+_GL_WARN_ON_USE (mbsrtowcs, "mbsrtowcs is unportable - "
+                 "use gnulib module mbsrtowcs for portability");
+# endif
+#endif
+
+
+/* Convert a string to a wide string.  */
+#if @GNULIB_MBSNRTOWCS@
+# if @REPLACE_MBSNRTOWCS@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef mbsnrtowcs
+#   define mbsnrtowcs rpl_mbsnrtowcs
+#  endif
+_GL_FUNCDECL_RPL (mbsnrtowcs, size_t,
+                  (wchar_t *dest, const char **srcp, size_t srclen, size_t len,
+                   mbstate_t *ps)
+                  _GL_ARG_NONNULL ((2)));
+_GL_CXXALIAS_RPL (mbsnrtowcs, size_t,
+                  (wchar_t *dest, const char **srcp, size_t srclen, size_t len,
+                   mbstate_t *ps));
+# else
+#  if !@HAVE_MBSNRTOWCS@
+_GL_FUNCDECL_SYS (mbsnrtowcs, size_t,
+                  (wchar_t *dest, const char **srcp, size_t srclen, size_t len,
+                   mbstate_t *ps)
+                  _GL_ARG_NONNULL ((2)));
+#  endif
+_GL_CXXALIAS_SYS (mbsnrtowcs, size_t,
+                  (wchar_t *dest, const char **srcp, size_t srclen, size_t len,
+                   mbstate_t *ps));
+# endif
+_GL_CXXALIASWARN (mbsnrtowcs);
+#elif defined GNULIB_POSIXCHECK
+# undef mbsnrtowcs
+# if HAVE_RAW_DECL_MBSNRTOWCS
+_GL_WARN_ON_USE (mbsnrtowcs, "mbsnrtowcs is unportable - "
+                 "use gnulib module mbsnrtowcs for portability");
+# endif
+#endif
+
+
+/* Convert a wide character to a multibyte character.  */
+#if @GNULIB_WCRTOMB@
+# if @REPLACE_WCRTOMB@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef wcrtomb
+#   define wcrtomb rpl_wcrtomb
+#  endif
+_GL_FUNCDECL_RPL (wcrtomb, size_t, (char *s, wchar_t wc, mbstate_t *ps));
+_GL_CXXALIAS_RPL (wcrtomb, size_t, (char *s, wchar_t wc, mbstate_t *ps));
+# else
+#  if !@HAVE_WCRTOMB@
+_GL_FUNCDECL_SYS (wcrtomb, size_t, (char *s, wchar_t wc, mbstate_t *ps));
+#  endif
+_GL_CXXALIAS_SYS (wcrtomb, size_t, (char *s, wchar_t wc, mbstate_t *ps));
+# endif
+_GL_CXXALIASWARN (wcrtomb);
+#elif defined GNULIB_POSIXCHECK
+# undef wcrtomb
+# if HAVE_RAW_DECL_WCRTOMB
+_GL_WARN_ON_USE (wcrtomb, "wcrtomb is unportable - "
+                 "use gnulib module wcrtomb for portability");
+# endif
+#endif
+
+
+/* Convert a wide string to a string.  */
+#if @GNULIB_WCSRTOMBS@
+# if @REPLACE_WCSRTOMBS@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef wcsrtombs
+#   define wcsrtombs rpl_wcsrtombs
+#  endif
+_GL_FUNCDECL_RPL (wcsrtombs, size_t,
+                  (char *dest, const wchar_t **srcp, size_t len, mbstate_t *ps)
+                  _GL_ARG_NONNULL ((2)));
+_GL_CXXALIAS_RPL (wcsrtombs, size_t,
+                  (char *dest, const wchar_t **srcp, size_t len,
+                   mbstate_t *ps));
+# else
+#  if !@HAVE_WCSRTOMBS@
+_GL_FUNCDECL_SYS (wcsrtombs, size_t,
+                  (char *dest, const wchar_t **srcp, size_t len, mbstate_t *ps)
+                  _GL_ARG_NONNULL ((2)));
+#  endif
+_GL_CXXALIAS_SYS (wcsrtombs, size_t,
+                  (char *dest, const wchar_t **srcp, size_t len,
+                   mbstate_t *ps));
+# endif
+_GL_CXXALIASWARN (wcsrtombs);
+#elif defined GNULIB_POSIXCHECK
+# undef wcsrtombs
+# if HAVE_RAW_DECL_WCSRTOMBS
+_GL_WARN_ON_USE (wcsrtombs, "wcsrtombs is unportable - "
+                 "use gnulib module wcsrtombs for portability");
+# endif
+#endif
+
+
+/* Convert a wide string to a string.  */
+#if @GNULIB_WCSNRTOMBS@
+# if @REPLACE_WCSNRTOMBS@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef wcsnrtombs
+#   define wcsnrtombs rpl_wcsnrtombs
+#  endif
+_GL_FUNCDECL_RPL (wcsnrtombs, size_t,
+                  (char *dest, const wchar_t **srcp, size_t srclen, size_t len,
+                   mbstate_t *ps)
+                  _GL_ARG_NONNULL ((2)));
+_GL_CXXALIAS_RPL (wcsnrtombs, size_t,
+                  (char *dest, const wchar_t **srcp, size_t srclen, size_t len,
+                   mbstate_t *ps));
+# else
+#  if !@HAVE_WCSNRTOMBS@
+_GL_FUNCDECL_SYS (wcsnrtombs, size_t,
+                  (char *dest, const wchar_t **srcp, size_t srclen, size_t len,
+                   mbstate_t *ps)
+                  _GL_ARG_NONNULL ((2)));
+#  endif
+_GL_CXXALIAS_SYS (wcsnrtombs, size_t,
+                  (char *dest, const wchar_t **srcp, size_t srclen, size_t len,
+                   mbstate_t *ps));
+# endif
+_GL_CXXALIASWARN (wcsnrtombs);
+#elif defined GNULIB_POSIXCHECK
+# undef wcsnrtombs
+# if HAVE_RAW_DECL_WCSNRTOMBS
+_GL_WARN_ON_USE (wcsnrtombs, "wcsnrtombs is unportable - "
+                 "use gnulib module wcsnrtombs for portability");
+# endif
+#endif
+
+
+/* Return the number of screen columns needed for WC.  */
+#if @GNULIB_WCWIDTH@
+# if @REPLACE_WCWIDTH@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef wcwidth
+#   define wcwidth rpl_wcwidth
+#  endif
+_GL_FUNCDECL_RPL (wcwidth, int, (wchar_t) _GL_ATTRIBUTE_PURE);
+_GL_CXXALIAS_RPL (wcwidth, int, (wchar_t));
+# else
+#  if !@HAVE_DECL_WCWIDTH@
+/* wcwidth exists but is not declared.  */
+_GL_FUNCDECL_SYS (wcwidth, int, (wchar_t) _GL_ATTRIBUTE_PURE);
+#  endif
+_GL_CXXALIAS_SYS (wcwidth, int, (wchar_t));
+# endif
+_GL_CXXALIASWARN (wcwidth);
+#elif defined GNULIB_POSIXCHECK
+# undef wcwidth
+# if HAVE_RAW_DECL_WCWIDTH
+_GL_WARN_ON_USE (wcwidth, "wcwidth is unportable - "
+                 "use gnulib module wcwidth for portability");
+# endif
+#endif
+
+
+/* Search N wide characters of S for C.  */
+#if @GNULIB_WMEMCHR@
+# if !@HAVE_WMEMCHR@
+_GL_FUNCDECL_SYS (wmemchr, wchar_t *, (const wchar_t *s, wchar_t c, size_t n)
+                                      _GL_ATTRIBUTE_PURE);
+# endif
+  /* On some systems, this function is defined as an overloaded function:
+       extern "C++" {
+         const wchar_t * std::wmemchr (const wchar_t *, wchar_t, size_t);
+         wchar_t * std::wmemchr (wchar_t *, wchar_t, size_t);
+       }  */
+_GL_CXXALIAS_SYS_CAST2 (wmemchr,
+                        wchar_t *, (const wchar_t *, wchar_t, size_t),
+                        const wchar_t *, (const wchar_t *, wchar_t, size_t));
+# if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 10) && !defined __UCLIBC__) \
+     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
+_GL_CXXALIASWARN1 (wmemchr, wchar_t *, (wchar_t *s, wchar_t c, size_t n));
+_GL_CXXALIASWARN1 (wmemchr, const wchar_t *,
+                   (const wchar_t *s, wchar_t c, size_t n));
+# else
+_GL_CXXALIASWARN (wmemchr);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef wmemchr
+# if HAVE_RAW_DECL_WMEMCHR
+_GL_WARN_ON_USE (wmemchr, "wmemchr is unportable - "
+                 "use gnulib module wmemchr for portability");
+# endif
+#endif
+
+
+/* Compare N wide characters of S1 and S2.  */
+#if @GNULIB_WMEMCMP@
+# if !@HAVE_WMEMCMP@
+_GL_FUNCDECL_SYS (wmemcmp, int,
+                  (const wchar_t *s1, const wchar_t *s2, size_t n)
+                  _GL_ATTRIBUTE_PURE);
+# endif
+_GL_CXXALIAS_SYS (wmemcmp, int,
+                  (const wchar_t *s1, const wchar_t *s2, size_t n));
+_GL_CXXALIASWARN (wmemcmp);
+#elif defined GNULIB_POSIXCHECK
+# undef wmemcmp
+# if HAVE_RAW_DECL_WMEMCMP
+_GL_WARN_ON_USE (wmemcmp, "wmemcmp is unportable - "
+                 "use gnulib module wmemcmp for portability");
+# endif
+#endif
+
+
+/* Copy N wide characters of SRC to DEST.  */
+#if @GNULIB_WMEMCPY@
+# if !@HAVE_WMEMCPY@
+_GL_FUNCDECL_SYS (wmemcpy, wchar_t *,
+                  (wchar_t *dest, const wchar_t *src, size_t n));
+# endif
+_GL_CXXALIAS_SYS (wmemcpy, wchar_t *,
+                  (wchar_t *dest, const wchar_t *src, size_t n));
+_GL_CXXALIASWARN (wmemcpy);
+#elif defined GNULIB_POSIXCHECK
+# undef wmemcpy
+# if HAVE_RAW_DECL_WMEMCPY
+_GL_WARN_ON_USE (wmemcpy, "wmemcpy is unportable - "
+                 "use gnulib module wmemcpy for portability");
+# endif
+#endif
+
+
+/* Copy N wide characters of SRC to DEST, guaranteeing correct behavior for
+   overlapping memory areas.  */
+#if @GNULIB_WMEMMOVE@
+# if !@HAVE_WMEMMOVE@
+_GL_FUNCDECL_SYS (wmemmove, wchar_t *,
+                  (wchar_t *dest, const wchar_t *src, size_t n));
+# endif
+_GL_CXXALIAS_SYS (wmemmove, wchar_t *,
+                  (wchar_t *dest, const wchar_t *src, size_t n));
+_GL_CXXALIASWARN (wmemmove);
+#elif defined GNULIB_POSIXCHECK
+# undef wmemmove
+# if HAVE_RAW_DECL_WMEMMOVE
+_GL_WARN_ON_USE (wmemmove, "wmemmove is unportable - "
+                 "use gnulib module wmemmove for portability");
+# endif
+#endif
+
+
+/* Set N wide characters of S to C.  */
+#if @GNULIB_WMEMSET@
+# if !@HAVE_WMEMSET@
+_GL_FUNCDECL_SYS (wmemset, wchar_t *, (wchar_t *s, wchar_t c, size_t n));
+# endif
+_GL_CXXALIAS_SYS (wmemset, wchar_t *, (wchar_t *s, wchar_t c, size_t n));
+_GL_CXXALIASWARN (wmemset);
+#elif defined GNULIB_POSIXCHECK
+# undef wmemset
+# if HAVE_RAW_DECL_WMEMSET
+_GL_WARN_ON_USE (wmemset, "wmemset is unportable - "
+                 "use gnulib module wmemset for portability");
+# endif
+#endif
+
+
+/* Return the number of wide characters in S.  */
+#if @GNULIB_WCSLEN@
+# if !@HAVE_WCSLEN@
+_GL_FUNCDECL_SYS (wcslen, size_t, (const wchar_t *s) _GL_ATTRIBUTE_PURE);
+# endif
+_GL_CXXALIAS_SYS (wcslen, size_t, (const wchar_t *s));
+_GL_CXXALIASWARN (wcslen);
+#elif defined GNULIB_POSIXCHECK
+# undef wcslen
+# if HAVE_RAW_DECL_WCSLEN
+_GL_WARN_ON_USE (wcslen, "wcslen is unportable - "
+                 "use gnulib module wcslen for portability");
+# endif
+#endif
+
+
+/* Return the number of wide characters in S, but at most MAXLEN.  */
+#if @GNULIB_WCSNLEN@
+# if !@HAVE_WCSNLEN@
+_GL_FUNCDECL_SYS (wcsnlen, size_t, (const wchar_t *s, size_t maxlen)
+                                   _GL_ATTRIBUTE_PURE);
+# endif
+_GL_CXXALIAS_SYS (wcsnlen, size_t, (const wchar_t *s, size_t maxlen));
+_GL_CXXALIASWARN (wcsnlen);
+#elif defined GNULIB_POSIXCHECK
+# undef wcsnlen
+# if HAVE_RAW_DECL_WCSNLEN
+_GL_WARN_ON_USE (wcsnlen, "wcsnlen is unportable - "
+                 "use gnulib module wcsnlen for portability");
+# endif
+#endif
+
+
+/* Copy SRC to DEST.  */
+#if @GNULIB_WCSCPY@
+# if !@HAVE_WCSCPY@
+_GL_FUNCDECL_SYS (wcscpy, wchar_t *, (wchar_t *dest, const wchar_t *src));
+# endif
+_GL_CXXALIAS_SYS (wcscpy, wchar_t *, (wchar_t *dest, const wchar_t *src));
+_GL_CXXALIASWARN (wcscpy);
+#elif defined GNULIB_POSIXCHECK
+# undef wcscpy
+# if HAVE_RAW_DECL_WCSCPY
+_GL_WARN_ON_USE (wcscpy, "wcscpy is unportable - "
+                 "use gnulib module wcscpy for portability");
+# endif
+#endif
+
+
+/* Copy SRC to DEST, returning the address of the terminating L'\0' in DEST.  */
+#if @GNULIB_WCPCPY@
+# if !@HAVE_WCPCPY@
+_GL_FUNCDECL_SYS (wcpcpy, wchar_t *, (wchar_t *dest, const wchar_t *src));
+# endif
+_GL_CXXALIAS_SYS (wcpcpy, wchar_t *, (wchar_t *dest, const wchar_t *src));
+_GL_CXXALIASWARN (wcpcpy);
+#elif defined GNULIB_POSIXCHECK
+# undef wcpcpy
+# if HAVE_RAW_DECL_WCPCPY
+_GL_WARN_ON_USE (wcpcpy, "wcpcpy is unportable - "
+                 "use gnulib module wcpcpy for portability");
+# endif
+#endif
+
+
+/* Copy no more than N wide characters of SRC to DEST.  */
+#if @GNULIB_WCSNCPY@
+# if !@HAVE_WCSNCPY@
+_GL_FUNCDECL_SYS (wcsncpy, wchar_t *,
+                  (wchar_t *dest, const wchar_t *src, size_t n));
+# endif
+_GL_CXXALIAS_SYS (wcsncpy, wchar_t *,
+                  (wchar_t *dest, const wchar_t *src, size_t n));
+_GL_CXXALIASWARN (wcsncpy);
+#elif defined GNULIB_POSIXCHECK
+# undef wcsncpy
+# if HAVE_RAW_DECL_WCSNCPY
+_GL_WARN_ON_USE (wcsncpy, "wcsncpy is unportable - "
+                 "use gnulib module wcsncpy for portability");
+# endif
+#endif
+
+
+/* Copy no more than N characters of SRC to DEST, returning the address of
+   the last character written into DEST.  */
+#if @GNULIB_WCPNCPY@
+# if !@HAVE_WCPNCPY@
+_GL_FUNCDECL_SYS (wcpncpy, wchar_t *,
+                  (wchar_t *dest, const wchar_t *src, size_t n));
+# endif
+_GL_CXXALIAS_SYS (wcpncpy, wchar_t *,
+                  (wchar_t *dest, const wchar_t *src, size_t n));
+_GL_CXXALIASWARN (wcpncpy);
+#elif defined GNULIB_POSIXCHECK
+# undef wcpncpy
+# if HAVE_RAW_DECL_WCPNCPY
+_GL_WARN_ON_USE (wcpncpy, "wcpncpy is unportable - "
+                 "use gnulib module wcpncpy for portability");
+# endif
+#endif
+
+
+/* Append SRC onto DEST.  */
+#if @GNULIB_WCSCAT@
+# if !@HAVE_WCSCAT@
+_GL_FUNCDECL_SYS (wcscat, wchar_t *, (wchar_t *dest, const wchar_t *src));
+# endif
+_GL_CXXALIAS_SYS (wcscat, wchar_t *, (wchar_t *dest, const wchar_t *src));
+_GL_CXXALIASWARN (wcscat);
+#elif defined GNULIB_POSIXCHECK
+# undef wcscat
+# if HAVE_RAW_DECL_WCSCAT
+_GL_WARN_ON_USE (wcscat, "wcscat is unportable - "
+                 "use gnulib module wcscat for portability");
+# endif
+#endif
+
+
+/* Append no more than N wide characters of SRC onto DEST.  */
+#if @GNULIB_WCSNCAT@
+# if !@HAVE_WCSNCAT@
+_GL_FUNCDECL_SYS (wcsncat, wchar_t *,
+                  (wchar_t *dest, const wchar_t *src, size_t n));
+# endif
+_GL_CXXALIAS_SYS (wcsncat, wchar_t *,
+                  (wchar_t *dest, const wchar_t *src, size_t n));
+_GL_CXXALIASWARN (wcsncat);
+#elif defined GNULIB_POSIXCHECK
+# undef wcsncat
+# if HAVE_RAW_DECL_WCSNCAT
+_GL_WARN_ON_USE (wcsncat, "wcsncat is unportable - "
+                 "use gnulib module wcsncat for portability");
+# endif
+#endif
+
+
+/* Compare S1 and S2.  */
+#if @GNULIB_WCSCMP@
+# if !@HAVE_WCSCMP@
+_GL_FUNCDECL_SYS (wcscmp, int, (const wchar_t *s1, const wchar_t *s2)
+                               _GL_ATTRIBUTE_PURE);
+# endif
+_GL_CXXALIAS_SYS (wcscmp, int, (const wchar_t *s1, const wchar_t *s2));
+_GL_CXXALIASWARN (wcscmp);
+#elif defined GNULIB_POSIXCHECK
+# undef wcscmp
+# if HAVE_RAW_DECL_WCSCMP
+_GL_WARN_ON_USE (wcscmp, "wcscmp is unportable - "
+                 "use gnulib module wcscmp for portability");
+# endif
+#endif
+
+
+/* Compare no more than N wide characters of S1 and S2.  */
+#if @GNULIB_WCSNCMP@
+# if !@HAVE_WCSNCMP@
+_GL_FUNCDECL_SYS (wcsncmp, int,
+                  (const wchar_t *s1, const wchar_t *s2, size_t n)
+                  _GL_ATTRIBUTE_PURE);
+# endif
+_GL_CXXALIAS_SYS (wcsncmp, int,
+                  (const wchar_t *s1, const wchar_t *s2, size_t n));
+_GL_CXXALIASWARN (wcsncmp);
+#elif defined GNULIB_POSIXCHECK
+# undef wcsncmp
+# if HAVE_RAW_DECL_WCSNCMP
+_GL_WARN_ON_USE (wcsncmp, "wcsncmp is unportable - "
+                 "use gnulib module wcsncmp for portability");
+# endif
+#endif
+
+
+/* Compare S1 and S2, ignoring case.  */
+#if @GNULIB_WCSCASECMP@
+# if !@HAVE_WCSCASECMP@
+_GL_FUNCDECL_SYS (wcscasecmp, int, (const wchar_t *s1, const wchar_t *s2)
+                                   _GL_ATTRIBUTE_PURE);
+# endif
+_GL_CXXALIAS_SYS (wcscasecmp, int, (const wchar_t *s1, const wchar_t *s2));
+_GL_CXXALIASWARN (wcscasecmp);
+#elif defined GNULIB_POSIXCHECK
+# undef wcscasecmp
+# if HAVE_RAW_DECL_WCSCASECMP
+_GL_WARN_ON_USE (wcscasecmp, "wcscasecmp is unportable - "
+                 "use gnulib module wcscasecmp for portability");
+# endif
+#endif
+
+
+/* Compare no more than N chars of S1 and S2, ignoring case.  */
+#if @GNULIB_WCSNCASECMP@
+# if !@HAVE_WCSNCASECMP@
+_GL_FUNCDECL_SYS (wcsncasecmp, int,
+                  (const wchar_t *s1, const wchar_t *s2, size_t n)
+                  _GL_ATTRIBUTE_PURE);
+# endif
+_GL_CXXALIAS_SYS (wcsncasecmp, int,
+                  (const wchar_t *s1, const wchar_t *s2, size_t n));
+_GL_CXXALIASWARN (wcsncasecmp);
+#elif defined GNULIB_POSIXCHECK
+# undef wcsncasecmp
+# if HAVE_RAW_DECL_WCSNCASECMP
+_GL_WARN_ON_USE (wcsncasecmp, "wcsncasecmp is unportable - "
+                 "use gnulib module wcsncasecmp for portability");
+# endif
+#endif
+
+
+/* Compare S1 and S2, both interpreted as appropriate to the LC_COLLATE
+   category of the current locale.  */
+#if @GNULIB_WCSCOLL@
+# if !@HAVE_WCSCOLL@
+_GL_FUNCDECL_SYS (wcscoll, int, (const wchar_t *s1, const wchar_t *s2));
+# endif
+_GL_CXXALIAS_SYS (wcscoll, int, (const wchar_t *s1, const wchar_t *s2));
+_GL_CXXALIASWARN (wcscoll);
+#elif defined GNULIB_POSIXCHECK
+# undef wcscoll
+# if HAVE_RAW_DECL_WCSCOLL
+_GL_WARN_ON_USE (wcscoll, "wcscoll is unportable - "
+                 "use gnulib module wcscoll for portability");
+# endif
+#endif
+
+
+/* Transform S2 into array pointed to by S1 such that if wcscmp is applied
+   to two transformed strings the result is the as applying 'wcscoll' to the
+   original strings.  */
+#if @GNULIB_WCSXFRM@
+# if !@HAVE_WCSXFRM@
+_GL_FUNCDECL_SYS (wcsxfrm, size_t, (wchar_t *s1, const wchar_t *s2, size_t n));
+# endif
+_GL_CXXALIAS_SYS (wcsxfrm, size_t, (wchar_t *s1, const wchar_t *s2, size_t n));
+_GL_CXXALIASWARN (wcsxfrm);
+#elif defined GNULIB_POSIXCHECK
+# undef wcsxfrm
+# if HAVE_RAW_DECL_WCSXFRM
+_GL_WARN_ON_USE (wcsxfrm, "wcsxfrm is unportable - "
+                 "use gnulib module wcsxfrm for portability");
+# endif
+#endif
+
+
+/* Duplicate S, returning an identical malloc'd string.  */
+#if @GNULIB_WCSDUP@
+# if !@HAVE_WCSDUP@
+_GL_FUNCDECL_SYS (wcsdup, wchar_t *, (const wchar_t *s));
+# endif
+_GL_CXXALIAS_SYS (wcsdup, wchar_t *, (const wchar_t *s));
+_GL_CXXALIASWARN (wcsdup);
+#elif defined GNULIB_POSIXCHECK
+# undef wcsdup
+# if HAVE_RAW_DECL_WCSDUP
+_GL_WARN_ON_USE (wcsdup, "wcsdup is unportable - "
+                 "use gnulib module wcsdup for portability");
+# endif
+#endif
+
+
+/* Find the first occurrence of WC in WCS.  */
+#if @GNULIB_WCSCHR@
+# if !@HAVE_WCSCHR@
+_GL_FUNCDECL_SYS (wcschr, wchar_t *, (const wchar_t *wcs, wchar_t wc)
+                                     _GL_ATTRIBUTE_PURE);
+# endif
+  /* On some systems, this function is defined as an overloaded function:
+       extern "C++" {
+         const wchar_t * std::wcschr (const wchar_t *, wchar_t);
+         wchar_t * std::wcschr (wchar_t *, wchar_t);
+       }  */
+_GL_CXXALIAS_SYS_CAST2 (wcschr,
+                        wchar_t *, (const wchar_t *, wchar_t),
+                        const wchar_t *, (const wchar_t *, wchar_t));
+# if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 10) && !defined __UCLIBC__) \
+     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
+_GL_CXXALIASWARN1 (wcschr, wchar_t *, (wchar_t *wcs, wchar_t wc));
+_GL_CXXALIASWARN1 (wcschr, const wchar_t *, (const wchar_t *wcs, wchar_t wc));
+# else
+_GL_CXXALIASWARN (wcschr);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef wcschr
+# if HAVE_RAW_DECL_WCSCHR
+_GL_WARN_ON_USE (wcschr, "wcschr is unportable - "
+                 "use gnulib module wcschr for portability");
+# endif
+#endif
+
+
+/* Find the last occurrence of WC in WCS.  */
+#if @GNULIB_WCSRCHR@
+# if !@HAVE_WCSRCHR@
+_GL_FUNCDECL_SYS (wcsrchr, wchar_t *, (const wchar_t *wcs, wchar_t wc)
+                                      _GL_ATTRIBUTE_PURE);
+# endif
+  /* On some systems, this function is defined as an overloaded function:
+       extern "C++" {
+         const wchar_t * std::wcsrchr (const wchar_t *, wchar_t);
+         wchar_t * std::wcsrchr (wchar_t *, wchar_t);
+       }  */
+_GL_CXXALIAS_SYS_CAST2 (wcsrchr,
+                        wchar_t *, (const wchar_t *, wchar_t),
+                        const wchar_t *, (const wchar_t *, wchar_t));
+# if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 10) && !defined __UCLIBC__) \
+     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
+_GL_CXXALIASWARN1 (wcsrchr, wchar_t *, (wchar_t *wcs, wchar_t wc));
+_GL_CXXALIASWARN1 (wcsrchr, const wchar_t *, (const wchar_t *wcs, wchar_t wc));
+# else
+_GL_CXXALIASWARN (wcsrchr);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef wcsrchr
+# if HAVE_RAW_DECL_WCSRCHR
+_GL_WARN_ON_USE (wcsrchr, "wcsrchr is unportable - "
+                 "use gnulib module wcsrchr for portability");
+# endif
+#endif
+
+
+/* Return the length of the initial segmet of WCS which consists entirely
+   of wide characters not in REJECT.  */
+#if @GNULIB_WCSCSPN@
+# if !@HAVE_WCSCSPN@
+_GL_FUNCDECL_SYS (wcscspn, size_t, (const wchar_t *wcs, const wchar_t *reject)
+                                   _GL_ATTRIBUTE_PURE);
+# endif
+_GL_CXXALIAS_SYS (wcscspn, size_t, (const wchar_t *wcs, const wchar_t *reject));
+_GL_CXXALIASWARN (wcscspn);
+#elif defined GNULIB_POSIXCHECK
+# undef wcscspn
+# if HAVE_RAW_DECL_WCSCSPN
+_GL_WARN_ON_USE (wcscspn, "wcscspn is unportable - "
+                 "use gnulib module wcscspn for portability");
+# endif
+#endif
+
+
+/* Return the length of the initial segmet of WCS which consists entirely
+   of wide characters in ACCEPT.  */
+#if @GNULIB_WCSSPN@
+# if !@HAVE_WCSSPN@
+_GL_FUNCDECL_SYS (wcsspn, size_t, (const wchar_t *wcs, const wchar_t *accept)
+                                  _GL_ATTRIBUTE_PURE);
+# endif
+_GL_CXXALIAS_SYS (wcsspn, size_t, (const wchar_t *wcs, const wchar_t *accept));
+_GL_CXXALIASWARN (wcsspn);
+#elif defined GNULIB_POSIXCHECK
+# undef wcsspn
+# if HAVE_RAW_DECL_WCSSPN
+_GL_WARN_ON_USE (wcsspn, "wcsspn is unportable - "
+                 "use gnulib module wcsspn for portability");
+# endif
+#endif
+
+
+/* Find the first occurrence in WCS of any character in ACCEPT.  */
+#if @GNULIB_WCSPBRK@
+# if !@HAVE_WCSPBRK@
+_GL_FUNCDECL_SYS (wcspbrk, wchar_t *,
+                  (const wchar_t *wcs, const wchar_t *accept)
+                  _GL_ATTRIBUTE_PURE);
+# endif
+  /* On some systems, this function is defined as an overloaded function:
+       extern "C++" {
+         const wchar_t * std::wcspbrk (const wchar_t *, const wchar_t *);
+         wchar_t * std::wcspbrk (wchar_t *, const wchar_t *);
+       }  */
+_GL_CXXALIAS_SYS_CAST2 (wcspbrk,
+                        wchar_t *, (const wchar_t *, const wchar_t *),
+                        const wchar_t *, (const wchar_t *, const wchar_t *));
+# if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 10) && !defined __UCLIBC__) \
+     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
+_GL_CXXALIASWARN1 (wcspbrk, wchar_t *,
+                   (wchar_t *wcs, const wchar_t *accept));
+_GL_CXXALIASWARN1 (wcspbrk, const wchar_t *,
+                   (const wchar_t *wcs, const wchar_t *accept));
+# else
+_GL_CXXALIASWARN (wcspbrk);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef wcspbrk
+# if HAVE_RAW_DECL_WCSPBRK
+_GL_WARN_ON_USE (wcspbrk, "wcspbrk is unportable - "
+                 "use gnulib module wcspbrk for portability");
+# endif
+#endif
+
+
+/* Find the first occurrence of NEEDLE in HAYSTACK.  */
+#if @GNULIB_WCSSTR@
+# if !@HAVE_WCSSTR@
+_GL_FUNCDECL_SYS (wcsstr, wchar_t *,
+                  (const wchar_t *haystack, const wchar_t *needle)
+                  _GL_ATTRIBUTE_PURE);
+# endif
+  /* On some systems, this function is defined as an overloaded function:
+       extern "C++" {
+         const wchar_t * std::wcsstr (const wchar_t *, const wchar_t *);
+         wchar_t * std::wcsstr (wchar_t *, const wchar_t *);
+       }  */
+_GL_CXXALIAS_SYS_CAST2 (wcsstr,
+                        wchar_t *, (const wchar_t *, const wchar_t *),
+                        const wchar_t *, (const wchar_t *, const wchar_t *));
+# if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 10) && !defined __UCLIBC__) \
+     && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
+_GL_CXXALIASWARN1 (wcsstr, wchar_t *,
+                   (wchar_t *haystack, const wchar_t *needle));
+_GL_CXXALIASWARN1 (wcsstr, const wchar_t *,
+                   (const wchar_t *haystack, const wchar_t *needle));
+# else
+_GL_CXXALIASWARN (wcsstr);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef wcsstr
+# if HAVE_RAW_DECL_WCSSTR
+_GL_WARN_ON_USE (wcsstr, "wcsstr is unportable - "
+                 "use gnulib module wcsstr for portability");
+# endif
+#endif
+
+
+/* Divide WCS into tokens separated by characters in DELIM.  */
+#if @GNULIB_WCSTOK@
+# if !@HAVE_WCSTOK@
+_GL_FUNCDECL_SYS (wcstok, wchar_t *,
+                  (wchar_t *wcs, const wchar_t *delim, wchar_t **ptr));
+# endif
+_GL_CXXALIAS_SYS (wcstok, wchar_t *,
+                  (wchar_t *wcs, const wchar_t *delim, wchar_t **ptr));
+_GL_CXXALIASWARN (wcstok);
+#elif defined GNULIB_POSIXCHECK
+# undef wcstok
+# if HAVE_RAW_DECL_WCSTOK
+_GL_WARN_ON_USE (wcstok, "wcstok is unportable - "
+                 "use gnulib module wcstok for portability");
+# endif
+#endif
+
+
+/* Determine number of column positions required for first N wide
+   characters (or fewer if S ends before this) in S.  */
+#if @GNULIB_WCSWIDTH@
+# if @REPLACE_WCSWIDTH@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef wcswidth
+#   define wcswidth rpl_wcswidth
+#  endif
+_GL_FUNCDECL_RPL (wcswidth, int, (const wchar_t *s, size_t n)
+                                 _GL_ATTRIBUTE_PURE);
+_GL_CXXALIAS_RPL (wcswidth, int, (const wchar_t *s, size_t n));
+# else
+#  if !@HAVE_WCSWIDTH@
+_GL_FUNCDECL_SYS (wcswidth, int, (const wchar_t *s, size_t n)
+                                 _GL_ATTRIBUTE_PURE);
+#  endif
+_GL_CXXALIAS_SYS (wcswidth, int, (const wchar_t *s, size_t n));
+# endif
+_GL_CXXALIASWARN (wcswidth);
+#elif defined GNULIB_POSIXCHECK
+# undef wcswidth
+# if HAVE_RAW_DECL_WCSWIDTH
+_GL_WARN_ON_USE (wcswidth, "wcswidth is unportable - "
+                 "use gnulib module wcswidth for portability");
+# endif
+#endif
+
+
+/* Convert *TP to a date and time wide string.  See
+   <http://pubs.opengroup.org/onlinepubs/9699919799/functions/wcsftime.html>.  */
+#if @GNULIB_WCSFTIME@
+# if @REPLACE_WCSFTIME@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef wcsftime
+#   define wcsftime rpl_wcsftime
+#  endif
+_GL_FUNCDECL_RPL (wcsftime, size_t, (wchar_t *__buf, size_t __bufsize,
+                                     const wchar_t *__fmt, const struct tm *__tp)
+                                    _GL_ARG_NONNULL ((1, 3, 4)));
+_GL_CXXALIAS_RPL (wcsftime, size_t, (wchar_t *__buf, size_t __bufsize,
+                                     const wchar_t *__fmt, const struct tm *__tp));
+# else
+#  if !@HAVE_WCSFTIME@
+_GL_FUNCDECL_SYS (wcsftime, size_t, (wchar_t *__buf, size_t __bufsize,
+                                     const wchar_t *__fmt, const struct tm *__tp)
+                                    _GL_ARG_NONNULL ((1, 3, 4)));
+#  endif
+_GL_CXXALIAS_SYS (wcsftime, size_t, (wchar_t *__buf, size_t __bufsize,
+                                     const wchar_t *__fmt, const struct tm *__tp));
+# endif
+_GL_CXXALIASWARN (wcsftime);
+#elif defined GNULIB_POSIXCHECK
+# undef wcsftime
+# if HAVE_RAW_DECL_WCSFTIME
+_GL_WARN_ON_USE (wcsftime, "wcsftime is unportable - "
+                 "use gnulib module wcsftime for portability");
+# endif
+#endif
+
+
+#endif /* _@GUARD_PREFIX@_WCHAR_H */
+#endif /* _@GUARD_PREFIX@_WCHAR_H */
+#endif
diff --git a/lib/wcrtomb.c b/lib/wcrtomb.c
new file mode 100644
index 0000000000..8f01972144
--- /dev/null
+++ b/lib/wcrtomb.c
@@ -0,0 +1,53 @@
+/* Convert wide character to multibyte character.
+   Copyright (C) 2008-2018 Free Software Foundation, Inc.
+   Written by Bruno Haible <[email-masked]>, 2008.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <wchar.h>
+
+#include <errno.h>
+#include <stdlib.h>
+
+
+size_t
+wcrtomb (char *s, wchar_t wc, mbstate_t *ps)
+{
+  /* This implementation of wcrtomb on top of wctomb() supports only
+     stateless encodings.  ps must be in the initial state.  */
+  if (ps != NULL && !mbsinit (ps))
+    {
+      errno = EINVAL;
+      return (size_t)(-1);
+    }
+
+  if (s == NULL)
+    /* We know the NUL wide character corresponds to the NUL character.  */
+    return 1;
+  else
+    {
+      int ret = wctomb (s, wc);
+
+      if (ret >= 0)
+        return ret;
+      else
+        {
+          errno = EILSEQ;
+          return (size_t)(-1);
+        }
+    }
+}
diff --git a/lib/wctype-h.c b/lib/wctype-h.c
new file mode 100644
index 0000000000..bb5f847e33
--- /dev/null
+++ b/lib/wctype-h.c
@@ -0,0 +1,4 @@
+/* Normally this would be wctype.c, but that name's already taken.  */
+#include <config.h>
+#define _GL_WCTYPE_INLINE _GL_EXTERN_INLINE
+#include "wctype.h"
diff --git a/lib/wctype.in.h b/lib/wctype.in.h
new file mode 100644
index 0000000000..3c6e5f2903
--- /dev/null
+++ b/lib/wctype.in.h
@@ -0,0 +1,533 @@
+/* A substitute for ISO C99 <wctype.h>, for platforms that lack it.
+
+   Copyright (C) 2006-2018 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible and Paul Eggert.  */
+
+/*
+ * ISO C 99 <wctype.h> for platforms that lack it.
+ * <http://www.opengroup.org/susv3xbd/wctype.h.html>
+ *
+ * iswctype, towctrans, towlower, towupper, wctrans, wctype,
+ * wctrans_t, and wctype_t are not yet implemented.
+ */
+
+#if __GNUC__ >= 3
+@PRAGMA_SYSTEM_HEADER@
+#endif
+@PRAGMA_COLUMNS@
+
+#if (defined __MINGW32__ && defined __CTYPE_H_SOURCED__)
+
+/* Special invocation convention:
+   - With MinGW 3.22, when <ctype.h> includes <wctype.h>, only some part of
+     <wctype.h> is being processed, which doesn't include the idempotency
+     guard.   */
+
+#@INCLUDE_NEXT@ @NEXT_WCTYPE_H@
+
+#else
+/* Normal invocation convention.  */
+
+#ifndef _@GUARD_PREFIX@_WCTYPE_H
+
+#if @HAVE_WINT_T@
+/* Solaris 2.5 has a bug: <wchar.h> must be included before <wctype.h>.
+   Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+# include <stddef.h>
+# include <stdio.h>
+# include <time.h>
+# include <wchar.h>
+#endif
+
+/* Native Windows (mingw, MSVC) have declarations of towupper, towlower, and
+   isw* functions in <ctype.h>, <wchar.h> as well as in <wctype.h>.  Include
+   <ctype.h>, <wchar.h> in advance to avoid rpl_ prefix being added to the
+   declarations.  */
+#if defined _WIN32 && ! defined __CYGWIN__
+# include <ctype.h>
+# include <wchar.h>
+#endif
+
+/* Include the original <wctype.h> if it exists.
+   BeOS 5 has the functions but no <wctype.h>.  */
+/* The include_next requires a split double-inclusion guard.  */
+#if @HAVE_WCTYPE_H@
+# @INCLUDE_NEXT@ @NEXT_WCTYPE_H@
+#endif
+
+#ifndef _@GUARD_PREFIX@_WCTYPE_H
+#define _@GUARD_PREFIX@_WCTYPE_H
+
+#ifndef _GL_INLINE_HEADER_BEGIN
+ #error "Please include config.h first."
+#endif
+_GL_INLINE_HEADER_BEGIN
+#ifndef _GL_WCTYPE_INLINE
+# define _GL_WCTYPE_INLINE _GL_INLINE
+#endif
+
+/* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
+
+/* The definition of _GL_WARN_ON_USE is copied here.  */
+
+/* Solaris 2.6 <wctype.h> includes <widec.h> which includes <euc.h> which
+   #defines a number of identifiers in the application namespace.  Revert
+   these #defines.  */
+#ifdef __sun
+# undef multibyte
+# undef eucw1
+# undef eucw2
+# undef eucw3
+# undef scrw1
+# undef scrw2
+# undef scrw3
+#endif
+
+/* Define wint_t and WEOF.  (Also done in wchar.in.h.)  */
+#if !@HAVE_WINT_T@ && !defined wint_t
+# define wint_t int
+# ifndef WEOF
+#  define WEOF -1
+# endif
+#else
+/* mingw and MSVC define wint_t as 'unsigned short' in <crtdefs.h> or
+   <stddef.h>.  This is too small: ISO C 99 section 7.24.1.(2) says that
+   wint_t must be "unchanged by default argument promotions".  Override it.  */
+# if @GNULIB_OVERRIDES_WINT_T@
+#  if !GNULIB_defined_wint_t
+#   if @HAVE_CRTDEFS_H@
+#    include <crtdefs.h>
+#   else
+#    include <stddef.h>
+#   endif
+typedef unsigned int rpl_wint_t;
+#   undef wint_t
+#   define wint_t rpl_wint_t
+#   define GNULIB_defined_wint_t 1
+#  endif
+# endif
+# ifndef WEOF
+#  define WEOF ((wint_t) -1)
+# endif
+#endif
+
+
+#if !GNULIB_defined_wctype_functions
+
+/* FreeBSD 4.4 to 4.11 has <wctype.h> but lacks the functions.
+   Linux libc5 has <wctype.h> and the functions but they are broken.
+   Assume all 11 functions (all isw* except iswblank) are implemented the
+   same way, or not at all.  */
+# if ! @HAVE_ISWCNTRL@ || @REPLACE_ISWCNTRL@
+
+/* IRIX 5.3 has macros but no functions, its isw* macros refer to an
+   undefined variable _ctmp_ and to <ctype.h> macros like _P, and they
+   refer to system functions like _iswctype that are not in the
+   standard C library.  Rather than try to get ancient buggy
+   implementations like this to work, just disable them.  */
+#  undef iswalnum
+#  undef iswalpha
+#  undef iswblank
+#  undef iswcntrl
+#  undef iswdigit
+#  undef iswgraph
+#  undef iswlower
+#  undef iswprint
+#  undef iswpunct
+#  undef iswspace
+#  undef iswupper
+#  undef iswxdigit
+#  undef towlower
+#  undef towupper
+
+/* Linux libc5 has <wctype.h> and the functions but they are broken.  */
+#  if @REPLACE_ISWCNTRL@
+#   if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#    define iswalnum rpl_iswalnum
+#    define iswalpha rpl_iswalpha
+#    define iswblank rpl_iswblank
+#    define iswcntrl rpl_iswcntrl
+#    define iswdigit rpl_iswdigit
+#    define iswgraph rpl_iswgraph
+#    define iswlower rpl_iswlower
+#    define iswprint rpl_iswprint
+#    define iswpunct rpl_iswpunct
+#    define iswspace rpl_iswspace
+#    define iswupper rpl_iswupper
+#    define iswxdigit rpl_iswxdigit
+#   endif
+#  endif
+#  if @REPLACE_TOWLOWER@
+#   if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#    define towlower rpl_towlower
+#    define towupper rpl_towupper
+#   endif
+#  endif
+
+_GL_WCTYPE_INLINE int
+#  if @REPLACE_ISWCNTRL@
+rpl_iswalnum
+#  else
+iswalnum
+#  endif
+         (wint_t wc)
+{
+  return ((wc >= '0' && wc <= '9')
+          || ((wc & ~0x20) >= 'A' && (wc & ~0x20) <= 'Z'));
+}
+
+_GL_WCTYPE_INLINE int
+#  if @REPLACE_ISWCNTRL@
+rpl_iswalpha
+#  else
+iswalpha
+#  endif
+         (wint_t wc)
+{
+  return (wc & ~0x20) >= 'A' && (wc & ~0x20) <= 'Z';
+}
+
+_GL_WCTYPE_INLINE int
+#  if @REPLACE_ISWCNTRL@
+rpl_iswblank
+#  else
+iswblank
+#  endif
+         (wint_t wc)
+{
+  return wc == ' ' || wc == '\t';
+}
+
+_GL_WCTYPE_INLINE int
+#  if @REPLACE_ISWCNTRL@
+rpl_iswcntrl
+#  else
+iswcntrl
+#  endif
+        (wint_t wc)
+{
+  return (wc & ~0x1f) == 0 || wc == 0x7f;
+}
+
+_GL_WCTYPE_INLINE int
+#  if @REPLACE_ISWCNTRL@
+rpl_iswdigit
+#  else
+iswdigit
+#  endif
+         (wint_t wc)
+{
+  return wc >= '0' && wc <= '9';
+}
+
+_GL_WCTYPE_INLINE int
+#  if @REPLACE_ISWCNTRL@
+rpl_iswgraph
+#  else
+iswgraph
+#  endif
+         (wint_t wc)
+{
+  return wc >= '!' && wc <= '~';
+}
+
+_GL_WCTYPE_INLINE int
+#  if @REPLACE_ISWCNTRL@
+rpl_iswlower
+#  else
+iswlower
+#  endif
+         (wint_t wc)
+{
+  return wc >= 'a' && wc <= 'z';
+}
+
+_GL_WCTYPE_INLINE int
+#  if @REPLACE_ISWCNTRL@
+rpl_iswprint
+#  else
+iswprint
+#  endif
+         (wint_t wc)
+{
+  return wc >= ' ' && wc <= '~';
+}
+
+_GL_WCTYPE_INLINE int
+#  if @REPLACE_ISWCNTRL@
+rpl_iswpunct
+#  else
+iswpunct
+#  endif
+         (wint_t wc)
+{
+  return (wc >= '!' && wc <= '~'
+          && !((wc >= '0' && wc <= '9')
+               || ((wc & ~0x20) >= 'A' && (wc & ~0x20) <= 'Z')));
+}
+
+_GL_WCTYPE_INLINE int
+#  if @REPLACE_ISWCNTRL@
+rpl_iswspace
+#  else
+iswspace
+#  endif
+         (wint_t wc)
+{
+  return (wc == ' ' || wc == '\t'
+          || wc == '\n' || wc == '\v' || wc == '\f' || wc == '\r');
+}
+
+_GL_WCTYPE_INLINE int
+#  if @REPLACE_ISWCNTRL@
+rpl_iswupper
+#  else
+iswupper
+#  endif
+         (wint_t wc)
+{
+  return wc >= 'A' && wc <= 'Z';
+}
+
+_GL_WCTYPE_INLINE int
+#  if @REPLACE_ISWCNTRL@
+rpl_iswxdigit
+#  else
+iswxdigit
+#  endif
+          (wint_t wc)
+{
+  return ((wc >= '0' && wc <= '9')
+          || ((wc & ~0x20) >= 'A' && (wc & ~0x20) <= 'F'));
+}
+
+_GL_WCTYPE_INLINE wint_t
+#  if @REPLACE_TOWLOWER@
+rpl_towlower
+#  else
+towlower
+#  endif
+         (wint_t wc)
+{
+  return (wc >= 'A' && wc <= 'Z' ? wc - 'A' + 'a' : wc);
+}
+
+_GL_WCTYPE_INLINE wint_t
+#  if @REPLACE_TOWLOWER@
+rpl_towupper
+#  else
+towupper
+#  endif
+         (wint_t wc)
+{
+  return (wc >= 'a' && wc <= 'z' ? wc - 'a' + 'A' : wc);
+}
+
+# elif @GNULIB_ISWBLANK@ && (! @HAVE_ISWBLANK@ || @REPLACE_ISWBLANK@)
+/* Only the iswblank function is missing.  */
+
+#  if @REPLACE_ISWBLANK@
+#   if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#    define iswblank rpl_iswblank
+#   endif
+_GL_FUNCDECL_RPL (iswblank, int, (wint_t wc));
+#  else
+_GL_FUNCDECL_SYS (iswblank, int, (wint_t wc));
+#  endif
+
+# endif
+
+# if defined __MINGW32__
+
+/* On native Windows, wchar_t is uint16_t, and wint_t is uint32_t.
+   The functions towlower and towupper are implemented in the MSVCRT library
+   to take a wchar_t argument and return a wchar_t result.  mingw declares
+   these functions to take a wint_t argument and return a wint_t result.
+   This means that:
+   1. When the user passes an argument outside the range 0x0000..0xFFFF, the
+      function will look only at the lower 16 bits.  This is allowed according
+      to POSIX.
+   2. The return value is returned in the lower 16 bits of the result register.
+      The upper 16 bits are random: whatever happened to be in that part of the
+      result register.  We need to fix this by adding a zero-extend from
+      wchar_t to wint_t after the call.  */
+
+_GL_WCTYPE_INLINE wint_t
+rpl_towlower (wint_t wc)
+{
+  return (wint_t) (wchar_t) towlower (wc);
+}
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   define towlower rpl_towlower
+#  endif
+
+_GL_WCTYPE_INLINE wint_t
+rpl_towupper (wint_t wc)
+{
+  return (wint_t) (wchar_t) towupper (wc);
+}
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   define towupper rpl_towupper
+#  endif
+
+# endif /* __MINGW32__ */
+
+# define GNULIB_defined_wctype_functions 1
+#endif
+
+#if @REPLACE_ISWCNTRL@
+_GL_CXXALIAS_RPL (iswalnum, int, (wint_t wc));
+_GL_CXXALIAS_RPL (iswalpha, int, (wint_t wc));
+_GL_CXXALIAS_RPL (iswcntrl, int, (wint_t wc));
+_GL_CXXALIAS_RPL (iswdigit, int, (wint_t wc));
+_GL_CXXALIAS_RPL (iswgraph, int, (wint_t wc));
+_GL_CXXALIAS_RPL (iswlower, int, (wint_t wc));
+_GL_CXXALIAS_RPL (iswprint, int, (wint_t wc));
+_GL_CXXALIAS_RPL (iswpunct, int, (wint_t wc));
+_GL_CXXALIAS_RPL (iswspace, int, (wint_t wc));
+_GL_CXXALIAS_RPL (iswupper, int, (wint_t wc));
+_GL_CXXALIAS_RPL (iswxdigit, int, (wint_t wc));
+#else
+_GL_CXXALIAS_SYS (iswalnum, int, (wint_t wc));
+_GL_CXXALIAS_SYS (iswalpha, int, (wint_t wc));
+_GL_CXXALIAS_SYS (iswcntrl, int, (wint_t wc));
+_GL_CXXALIAS_SYS (iswdigit, int, (wint_t wc));
+_GL_CXXALIAS_SYS (iswgraph, int, (wint_t wc));
+_GL_CXXALIAS_SYS (iswlower, int, (wint_t wc));
+_GL_CXXALIAS_SYS (iswprint, int, (wint_t wc));
+_GL_CXXALIAS_SYS (iswpunct, int, (wint_t wc));
+_GL_CXXALIAS_SYS (iswspace, int, (wint_t wc));
+_GL_CXXALIAS_SYS (iswupper, int, (wint_t wc));
+_GL_CXXALIAS_SYS (iswxdigit, int, (wint_t wc));
+#endif
+_GL_CXXALIASWARN (iswalnum);
+_GL_CXXALIASWARN (iswalpha);
+_GL_CXXALIASWARN (iswcntrl);
+_GL_CXXALIASWARN (iswdigit);
+_GL_CXXALIASWARN (iswgraph);
+_GL_CXXALIASWARN (iswlower);
+_GL_CXXALIASWARN (iswprint);
+_GL_CXXALIASWARN (iswpunct);
+_GL_CXXALIASWARN (iswspace);
+_GL_CXXALIASWARN (iswupper);
+_GL_CXXALIASWARN (iswxdigit);
+
+#if @GNULIB_ISWBLANK@
+# if @REPLACE_ISWCNTRL@ || @REPLACE_ISWBLANK@
+_GL_CXXALIAS_RPL (iswblank, int, (wint_t wc));
+# else
+_GL_CXXALIAS_SYS (iswblank, int, (wint_t wc));
+# endif
+_GL_CXXALIASWARN (iswblank);
+#endif
+
+#if !@HAVE_WCTYPE_T@
+# if !GNULIB_defined_wctype_t
+typedef void * wctype_t;
+#  define GNULIB_defined_wctype_t 1
+# endif
+#endif
+
+/* Get a descriptor for a wide character property.  */
+#if @GNULIB_WCTYPE@
+# if !@HAVE_WCTYPE_T@
+_GL_FUNCDECL_SYS (wctype, wctype_t, (const char *name));
+# endif
+_GL_CXXALIAS_SYS (wctype, wctype_t, (const char *name));
+_GL_CXXALIASWARN (wctype);
+#elif defined GNULIB_POSIXCHECK
+# undef wctype
+# if HAVE_RAW_DECL_WCTYPE
+_GL_WARN_ON_USE (wctype, "wctype is unportable - "
+                 "use gnulib module wctype for portability");
+# endif
+#endif
+
+/* Test whether a wide character has a given property.
+   The argument WC must be either a wchar_t value or WEOF.
+   The argument DESC must have been returned by the wctype() function.  */
+#if @GNULIB_ISWCTYPE@
+# if !@HAVE_WCTYPE_T@
+_GL_FUNCDECL_SYS (iswctype, int, (wint_t wc, wctype_t desc));
+# endif
+_GL_CXXALIAS_SYS (iswctype, int, (wint_t wc, wctype_t desc));
+_GL_CXXALIASWARN (iswctype);
+#elif defined GNULIB_POSIXCHECK
+# undef iswctype
+# if HAVE_RAW_DECL_ISWCTYPE
+_GL_WARN_ON_USE (iswctype, "iswctype is unportable - "
+                 "use gnulib module iswctype for portability");
+# endif
+#endif
+
+#if @REPLACE_TOWLOWER@ || defined __MINGW32__
+_GL_CXXALIAS_RPL (towlower, wint_t, (wint_t wc));
+_GL_CXXALIAS_RPL (towupper, wint_t, (wint_t wc));
+#else
+_GL_CXXALIAS_SYS (towlower, wint_t, (wint_t wc));
+_GL_CXXALIAS_SYS (towupper, wint_t, (wint_t wc));
+#endif
+_GL_CXXALIASWARN (towlower);
+_GL_CXXALIASWARN (towupper);
+
+#if !@HAVE_WCTRANS_T@
+# if !GNULIB_defined_wctrans_t
+typedef void * wctrans_t;
+#  define GNULIB_defined_wctrans_t 1
+# endif
+#endif
+
+/* Get a descriptor for a wide character case conversion.  */
+#if @GNULIB_WCTRANS@
+# if !@HAVE_WCTRANS_T@
+_GL_FUNCDECL_SYS (wctrans, wctrans_t, (const char *name));
+# endif
+_GL_CXXALIAS_SYS (wctrans, wctrans_t, (const char *name));
+_GL_CXXALIASWARN (wctrans);
+#elif defined GNULIB_POSIXCHECK
+# undef wctrans
+# if HAVE_RAW_DECL_WCTRANS
+_GL_WARN_ON_USE (wctrans, "wctrans is unportable - "
+                 "use gnulib module wctrans for portability");
+# endif
+#endif
+
+/* Perform a given case conversion on a wide character.
+   The argument WC must be either a wchar_t value or WEOF.
+   The argument DESC must have been returned by the wctrans() function.  */
+#if @GNULIB_TOWCTRANS@
+# if !@HAVE_WCTRANS_T@
+_GL_FUNCDECL_SYS (towctrans, wint_t, (wint_t wc, wctrans_t desc));
+# endif
+_GL_CXXALIAS_SYS (towctrans, wint_t, (wint_t wc, wctrans_t desc));
+_GL_CXXALIASWARN (towctrans);
+#elif defined GNULIB_POSIXCHECK
+# undef towctrans
+# if HAVE_RAW_DECL_TOWCTRANS
+_GL_WARN_ON_USE (towctrans, "towctrans is unportable - "
+                 "use gnulib module towctrans for portability");
+# endif
+#endif
+
+_GL_INLINE_HEADER_END
+
+#endif /* _@GUARD_PREFIX@_WCTYPE_H */
+#endif /* _@GUARD_PREFIX@_WCTYPE_H */
+#endif
diff --git a/lisp/char-fold.el b/lisp/char-fold.el
index 9c05e364df..311fe885a9 100644
--- a/lisp/char-fold.el
+++ b/lisp/char-fold.el
@@ -214,7 +214,7 @@ char-fold-to-regexp
     (when (> spaces 0)
       (push (char-fold--make-space-string spaces) out))
     (let ((regexp (apply #'concat (nreverse out))))
-      ;; Limited by `MAX_BUF_SIZE' in `regex.c'.
+      ;; Limited by MAX_BUF_SIZE in regex-emacs.c.
       (if (> (length regexp) 5000)
           (regexp-quote string)
         regexp))))
diff --git a/m4/btowc.m4 b/m4/btowc.m4
new file mode 100644
index 0000000000..8acdffc514
--- /dev/null
+++ b/m4/btowc.m4
@@ -0,0 +1,120 @@
+# btowc.m4 serial 11
+dnl Copyright (C) 2008-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_BTOWC],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+
+  dnl Check whether <wchar.h> is usable at all, first. Otherwise the test
+  dnl program below may lead to an endless loop. See
+  dnl <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42440>.
+  AC_REQUIRE([gl_WCHAR_H_INLINE_OK])
+
+  AC_CHECK_FUNCS_ONCE([btowc])
+  if test $ac_cv_func_btowc = no; then
+    HAVE_BTOWC=0
+  else
+
+    AC_REQUIRE([AC_PROG_CC])
+    AC_REQUIRE([gt_LOCALE_FR])
+    AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+    dnl Cygwin 1.7.2 btowc('\0') is WEOF, not 0.
+    AC_CACHE_CHECK([whether btowc(0) is correct],
+      [gl_cv_func_btowc_nul],
+      [
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <string.h>
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+int main ()
+{
+  if (btowc ('\0') != 0)
+    return 1;
+  return 0;
+}]])],
+          [gl_cv_func_btowc_nul=yes],
+          [gl_cv_func_btowc_nul=no],
+          [
+changequote(,)dnl
+           case "$host_os" in
+                      # Guess no on Cygwin.
+             cygwin*) gl_cv_func_btowc_nul="guessing no" ;;
+                      # Guess yes on native Windows.
+             mingw*)  gl_cv_func_btowc_nul="guessing yes" ;;
+                      # Guess yes otherwise.
+             *)       gl_cv_func_btowc_nul="guessing yes" ;;
+           esac
+changequote([,])dnl
+          ])
+      ])
+
+    dnl IRIX 6.5 btowc(EOF) is 0xFF, not WEOF.
+    AC_CACHE_CHECK([whether btowc(EOF) is correct],
+      [gl_cv_func_btowc_eof],
+      [
+        dnl Initial guess, used when cross-compiling or when no suitable locale
+        dnl is present.
+changequote(,)dnl
+        case "$host_os" in
+                  # Guess no on IRIX.
+          irix*)  gl_cv_func_btowc_eof="guessing no" ;;
+                  # Guess yes on native Windows.
+          mingw*) gl_cv_func_btowc_eof="guessing yes" ;;
+                  # Guess yes otherwise.
+          *)      gl_cv_func_btowc_eof="guessing yes" ;;
+        esac
+changequote([,])dnl
+        if test $LOCALE_FR != none; then
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+int main ()
+{
+  if (setlocale (LC_ALL, "$LOCALE_FR") != NULL)
+    {
+      if (btowc (EOF) != WEOF)
+        return 1;
+    }
+  return 0;
+}]])],
+            [gl_cv_func_btowc_eof=yes],
+            [gl_cv_func_btowc_eof=no],
+            [:])
+        fi
+      ])
+
+    case "$gl_cv_func_btowc_nul" in
+      *yes) ;;
+      *) REPLACE_BTOWC=1 ;;
+    esac
+    case "$gl_cv_func_btowc_eof" in
+      *yes) ;;
+      *) REPLACE_BTOWC=1 ;;
+    esac
+  fi
+])
+
+# Prerequisites of lib/btowc.c.
+AC_DEFUN([gl_PREREQ_BTOWC], [
+  :
+])
diff --git a/m4/builtin-expect.m4 b/m4/builtin-expect.m4
new file mode 100644
index 0000000000..a1eaf965b4
--- /dev/null
+++ b/m4/builtin-expect.m4
@@ -0,0 +1,49 @@
+dnl Check for __builtin_expect.
+
+dnl Copyright 2016-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Paul Eggert.
+
+AC_DEFUN([gl___BUILTIN_EXPECT],
+[
+  AC_CACHE_CHECK([for __builtin_expect],
+    [gl_cv___builtin_expect],
+    [AC_LINK_IFELSE(
+       [AC_LANG_SOURCE([[
+         int
+         main (int argc, char **argv)
+         {
+           argc = __builtin_expect (argc, 100);
+           return argv[argc != 100][0];
+         }]])],
+       [gl_cv___builtin_expect=yes],
+       [AC_LINK_IFELSE(
+          [AC_LANG_SOURCE([[
+             #include <builtins.h>
+             int
+             main (int argc, char **argv)
+             {
+               argc = __builtin_expect (argc, 100);
+               return argv[argc != 100][0];
+             }]])],
+          [gl_cv___builtin_expect="in <builtins.h>"],
+          [gl_cv___builtin_expect=no])])])
+  if test "$gl_cv___builtin_expect" = yes; then
+    AC_DEFINE([HAVE___BUILTIN_EXPECT], [1])
+  elif test "$gl_cv___builtin_expect" = "in <builtins.h>"; then
+    AC_DEFINE([HAVE___BUILTIN_EXPECT], [2])
+  fi
+  AH_VERBATIM([HAVE___BUILTIN_EXPECT],
+    [/* Define to 1 if the compiler supports __builtin_expect,
+   and to 2 if <builtins.h> does.  */
+#undef HAVE___BUILTIN_EXPECT
+#ifndef HAVE___BUILTIN_EXPECT
+# define __builtin_expect(e, c) (e)
+#elif HAVE___BUILTIN_EXPECT == 2
+# include <builtins.h>
+#endif
+    ])
+])
diff --git a/m4/codeset.m4 b/m4/codeset.m4
new file mode 100644
index 0000000000..bc98201e39
--- /dev/null
+++ b/m4/codeset.m4
@@ -0,0 +1,24 @@
+# codeset.m4 serial 5 (gettext-0.18.2)
+dnl Copyright (C) 2000-2002, 2006, 2008-2014, 2016 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+AC_DEFUN([AM_LANGINFO_CODESET],
+[
+  AC_CACHE_CHECK([for nl_langinfo and CODESET], [am_cv_langinfo_codeset],
+    [AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <langinfo.h>]],
+          [[char* cs = nl_langinfo(CODESET); return !cs;]])],
+       [am_cv_langinfo_codeset=yes],
+       [am_cv_langinfo_codeset=no])
+    ])
+  if test $am_cv_langinfo_codeset = yes; then
+    AC_DEFINE([HAVE_LANGINFO_CODESET], [1],
+      [Define if you have <langinfo.h> and nl_langinfo(CODESET).])
+  fi
+])
diff --git a/m4/eealloc.m4 b/m4/eealloc.m4
new file mode 100644
index 0000000000..a5a4e267d8
--- /dev/null
+++ b/m4/eealloc.m4
@@ -0,0 +1,31 @@
+# eealloc.m4 serial 3
+dnl Copyright (C) 2003, 2009-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_EEALLOC],
+[
+  AC_REQUIRE([gl_EEMALLOC])
+  AC_REQUIRE([gl_EEREALLOC])
+])
+
+AC_DEFUN([gl_EEMALLOC],
+[
+  _AC_FUNC_MALLOC_IF(
+    [gl_cv_func_malloc_0_nonnull=1],
+    [gl_cv_func_malloc_0_nonnull=0])
+  AC_DEFINE_UNQUOTED([MALLOC_0_IS_NONNULL], [$gl_cv_func_malloc_0_nonnull],
+    [If malloc(0) is != NULL, define this to 1.  Otherwise define this
+     to 0.])
+])
+
+AC_DEFUN([gl_EEREALLOC],
+[
+  _AC_FUNC_REALLOC_IF(
+    [gl_cv_func_realloc_0_nonnull=1],
+    [gl_cv_func_realloc_0_nonnull=0])
+  AC_DEFINE_UNQUOTED([REALLOC_0_IS_NONNULL], [$gl_cv_func_realloc_0_nonnull],
+    [If realloc(NULL,0) is != NULL, define this to 1.  Otherwise define this
+     to 0.])
+])
diff --git a/m4/glibc21.m4 b/m4/glibc21.m4
new file mode 100644
index 0000000000..126aa1a959
--- /dev/null
+++ b/m4/glibc21.m4
@@ -0,0 +1,34 @@
+# glibc21.m4 serial 5
+dnl Copyright (C) 2000-2002, 2004, 2008, 2010-2018 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# Test for the GNU C Library, version 2.1 or newer, or uClibc.
+# From Bruno Haible.
+
+AC_DEFUN([gl_GLIBC21],
+  [
+    AC_CACHE_CHECK([whether we are using the GNU C Library >= 2.1 or uClibc],
+      [ac_cv_gnu_library_2_1],
+      [AC_EGREP_CPP([Lucky],
+        [
+#include <features.h>
+#ifdef __GNU_LIBRARY__
+ #if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1) || (__GLIBC__ > 2)
+  Lucky GNU user
+ #endif
+#endif
+#ifdef __UCLIBC__
+ Lucky user
+#endif
+        ],
+        [ac_cv_gnu_library_2_1=yes],
+        [ac_cv_gnu_library_2_1=no])
+      ]
+    )
+    AC_SUBST([GLIBC21])
+    GLIBC21="$ac_cv_gnu_library_2_1"
+  ]
+)
diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
index a6e3be3815..3118fea54b 100644
--- a/m4/gnulib-comp.m4
+++ b/m4/gnulib-comp.m4
@@ -48,6 +48,8 @@ AC_DEFUN
   # Code from module allocator:
   # Code from module at-internal:
   # Code from module binary-io:
+  # Code from module btowc:
+  # Code from module builtin-expect:
   # Code from module byteswap:
   # Code from module c-ctype:
   # Code from module c-strcase:
@@ -101,22 +103,31 @@ AC_DEFUN
   # Code from module gettimeofday:
   # Code from module gitlog-to-changelog:
   # Code from module group-member:
+  # Code from module hard-locale:
   # Code from module ignore-value:
   # Code from module include_next:
   # Code from module intprops:
   # Code from module inttypes-incomplete:
+  # Code from module langinfo:
   # Code from module largefile:
   AC_REQUIRE([AC_SYS_LARGEFILE])
   # Code from module limits-h:
+  # Code from module localcharset:
+  # Code from module locale:
+  # Code from module localeconv:
   # Code from module localtime-buffer:
   # Code from module lstat:
   # Code from module manywarnings:
+  # Code from module mbrtowc:
+  # Code from module mbsinit:
+  # Code from module mbtowc:
   # Code from module memrchr:
   # Code from module minmax:
   # Code from module mkostemp:
   # Code from module mktime:
   # Code from module mktime-internal:
   # Code from module multiarch:
+  # Code from module nl_langinfo:
   # Code from module nocrash:
   # Code from module nstrftime:
   # Code from module open:
@@ -128,6 +139,7 @@ AC_DEFUN
   # Code from module qcopy-acl:
   # Code from module readlink:
   # Code from module readlinkat:
+  # Code from module regex:
   # Code from module root-uid:
   # Code from module sig2str:
   # Code from module signal-h:
@@ -145,6 +157,7 @@ AC_DEFUN
   # Code from module stdio:
   # Code from module stdlib:
   # Code from module stpcpy:
+  # Code from module streq:
   # Code from module string:
   # Code from module strtoimax:
   # Code from module strtoll:
@@ -171,6 +184,9 @@ AC_DEFUN
   # Code from module verify:
   # Code from module vla:
   # Code from module warnings:
+  # Code from module wchar:
+  # Code from module wcrtomb:
+  # Code from module wctype-h:
   # Code from module xalloc-oversized:
 ])
 
@@ -356,6 +372,11 @@ AC_DEFUN
     AC_LIBOBJ([readlinkat])
   fi
   gl_UNISTD_MODULE_INDICATOR([readlinkat])
+  gl_REGEX
+  if test $ac_use_included_regex = yes; then
+    AC_LIBOBJ([regex])
+    gl_PREREQ_REGEX
+  fi
   gl_FUNC_SIG2STR
   if test $ac_cv_func_sig2str = no; then
     AC_LIBOBJ([sig2str])
@@ -423,6 +444,8 @@ AC_DEFUN
   gl_UTIMENS
   AC_C_VARARRAYS
   gl_gnulib_enabled_260941c0e5dc67ec9e87d1fb321c300b=false
+  gl_gnulib_enabled_btowc=false
+  gl_gnulib_enabled_37f71b604aa9c54446783d80f42fe547=false
   gl_gnulib_enabled_cloexec=false
   gl_gnulib_enabled_dirfd=false
   gl_gnulib_enabled_dosname=false
@@ -431,12 +454,25 @@ AC_DEFUN
   gl_gnulib_enabled_getgroups=false
   gl_gnulib_enabled_be453cec5eecf5731a274f2de7f2db36=false
   gl_gnulib_enabled_a9786850e999ae65a836a6041e8e5ed1=false
+  gl_gnulib_enabled_30838f5439487421042f2225bed3af76=false
+  gl_gnulib_enabled_langinfo=false
+  gl_gnulib_enabled_localcharset=false
+  gl_gnulib_enabled_locale=false
+  gl_gnulib_enabled_localeconv=false
   gl_gnulib_enabled_2049e887c7e5308faad27b3f894bb8c9=false
+  gl_gnulib_enabled_mbrtowc=false
+  gl_gnulib_enabled_mbsinit=false
+  gl_gnulib_enabled_mbtowc=false
   gl_gnulib_enabled_5264294aa0a5557541b53c8c741f7f31=false
+  gl_gnulib_enabled_nl_langinfo=false
   gl_gnulib_enabled_open=false
   gl_gnulib_enabled_03e0aaad4cb89ca757653bd367a6ccb7=false
   gl_gnulib_enabled_6099e9737f757db36c47fa9d9f02e88c=false
+  gl_gnulib_enabled_streq=false
   gl_gnulib_enabled_strtoll=false
+  gl_gnulib_enabled_wchar=false
+  gl_gnulib_enabled_wcrtomb=false
+  gl_gnulib_enabled_3dcce957eadc896e63ab5f137947b410=false
   gl_gnulib_enabled_682e609604ccaac6be382e4ee3a4eaec=false
   func_gl_gnulib_m4code_260941c0e5dc67ec9e87d1fb321c300b ()
   {
@@ -446,6 +482,29 @@ AC_DEFUN
       func_gl_gnulib_m4code_open
     fi
   }
+  func_gl_gnulib_m4code_btowc ()
+  {
+    if ! $gl_gnulib_enabled_btowc; then
+      gl_FUNC_BTOWC
+      if test $HAVE_BTOWC = 0 || test $REPLACE_BTOWC = 1; then
+        AC_LIBOBJ([btowc])
+        gl_PREREQ_BTOWC
+      fi
+      gl_WCHAR_MODULE_INDICATOR([btowc])
+      gl_gnulib_enabled_btowc=true
+      if test $HAVE_BTOWC = 0 || test $REPLACE_BTOWC = 1; then
+        func_gl_gnulib_m4code_mbtowc
+      fi
+      func_gl_gnulib_m4code_wchar
+    fi
+  }
+  func_gl_gnulib_m4code_37f71b604aa9c54446783d80f42fe547 ()
+  {
+    if ! $gl_gnulib_enabled_37f71b604aa9c54446783d80f42fe547; then
+      gl___BUILTIN_EXPECT
+      gl_gnulib_enabled_37f71b604aa9c54446783d80f42fe547=true
+    fi
+  }
   func_gl_gnulib_m4code_cloexec ()
   {
     if ! $gl_gnulib_enabled_cloexec; then
@@ -537,6 +596,49 @@ AC_DEFUN
       fi
     fi
   }
+  func_gl_gnulib_m4code_30838f5439487421042f2225bed3af76 ()
+  {
+    if ! $gl_gnulib_enabled_30838f5439487421042f2225bed3af76; then
+      gl_gnulib_enabled_30838f5439487421042f2225bed3af76=true
+    fi
+  }
+  func_gl_gnulib_m4code_langinfo ()
+  {
+    if ! $gl_gnulib_enabled_langinfo; then
+      gl_LANGINFO_H
+      gl_gnulib_enabled_langinfo=true
+    fi
+  }
+  func_gl_gnulib_m4code_localcharset ()
+  {
+    if ! $gl_gnulib_enabled_localcharset; then
+      gl_LOCALCHARSET
+      dnl For backward compatibility. Some packages still use this.
+      LOCALCHARSET_TESTS_ENVIRONMENT=
+      AC_SUBST([LOCALCHARSET_TESTS_ENVIRONMENT])
+      gl_gnulib_enabled_localcharset=true
+    fi
+  }
+  func_gl_gnulib_m4code_locale ()
+  {
+    if ! $gl_gnulib_enabled_locale; then
+      gl_LOCALE_H
+      gl_gnulib_enabled_locale=true
+    fi
+  }
+  func_gl_gnulib_m4code_localeconv ()
+  {
+    if ! $gl_gnulib_enabled_localeconv; then
+      gl_FUNC_LOCALECONV
+      if test $REPLACE_LOCALECONV = 1; then
+        AC_LIBOBJ([localeconv])
+        gl_PREREQ_LOCALECONV
+      fi
+      gl_LOCALE_MODULE_INDICATOR([localeconv])
+      gl_gnulib_enabled_localeconv=true
+      func_gl_gnulib_m4code_locale
+    fi
+  }
   func_gl_gnulib_m4code_2049e887c7e5308faad27b3f894bb8c9 ()
   {
     if ! $gl_gnulib_enabled_2049e887c7e5308faad27b3f894bb8c9; then
@@ -545,6 +647,65 @@ AC_DEFUN
       gl_gnulib_enabled_2049e887c7e5308faad27b3f894bb8c9=true
     fi
   }
+  func_gl_gnulib_m4code_mbrtowc ()
+  {
+    if ! $gl_gnulib_enabled_mbrtowc; then
+      gl_FUNC_MBRTOWC
+      if test $HAVE_MBRTOWC = 0 || test $REPLACE_MBRTOWC = 1; then
+        AC_LIBOBJ([mbrtowc])
+        gl_PREREQ_MBRTOWC
+      fi
+      gl_WCHAR_MODULE_INDICATOR([mbrtowc])
+      gl_gnulib_enabled_mbrtowc=true
+      if test $HAVE_MBRTOWC = 0 || test $REPLACE_MBRTOWC = 1; then
+        func_gl_gnulib_m4code_30838f5439487421042f2225bed3af76
+      fi
+      if test $HAVE_MBRTOWC = 0 || test $REPLACE_MBRTOWC = 1; then
+        func_gl_gnulib_m4code_localcharset
+      fi
+      if test $HAVE_MBRTOWC = 0 || test $REPLACE_MBRTOWC = 1; then
+        func_gl_gnulib_m4code_mbsinit
+      fi
+      if test $HAVE_MBRTOWC = 0 || test $REPLACE_MBRTOWC = 1; then
+        func_gl_gnulib_m4code_streq
+      fi
+      func_gl_gnulib_m4code_wchar
+    fi
+  }
+  func_gl_gnulib_m4code_mbsinit ()
+  {
+    if ! $gl_gnulib_enabled_mbsinit; then
+      gl_FUNC_MBSINIT
+      if test $HAVE_MBSINIT = 0 || test $REPLACE_MBSINIT = 1; then
+        AC_LIBOBJ([mbsinit])
+        gl_PREREQ_MBSINIT
+      fi
+      gl_WCHAR_MODULE_INDICATOR([mbsinit])
+      gl_gnulib_enabled_mbsinit=true
+      if test $HAVE_MBSINIT = 0 || test $REPLACE_MBSINIT = 1; then
+        func_gl_gnulib_m4code_mbrtowc
+      fi
+      func_gl_gnulib_m4code_wchar
+    fi
+  }
+  func_gl_gnulib_m4code_mbtowc ()
+  {
+    if ! $gl_gnulib_enabled_mbtowc; then
+      gl_FUNC_MBTOWC
+      if test $REPLACE_MBTOWC = 1; then
+        AC_LIBOBJ([mbtowc])
+        gl_PREREQ_MBTOWC
+      fi
+      gl_STDLIB_MODULE_INDICATOR([mbtowc])
+      gl_gnulib_enabled_mbtowc=true
+      if test $REPLACE_MBTOWC = 1; then
+        func_gl_gnulib_m4code_mbrtowc
+      fi
+      if test $REPLACE_MBTOWC = 1; then
+        func_gl_gnulib_m4code_wchar
+      fi
+    fi
+  }
   func_gl_gnulib_m4code_5264294aa0a5557541b53c8c741f7f31 ()
   {
     if ! $gl_gnulib_enabled_5264294aa0a5557541b53c8c741f7f31; then
@@ -556,6 +717,21 @@ AC_DEFUN
       gl_gnulib_enabled_5264294aa0a5557541b53c8c741f7f31=true
     fi
   }
+  func_gl_gnulib_m4code_nl_langinfo ()
+  {
+    if ! $gl_gnulib_enabled_nl_langinfo; then
+      gl_FUNC_NL_LANGINFO
+      if test $HAVE_NL_LANGINFO = 0 || test $REPLACE_NL_LANGINFO = 1; then
+        AC_LIBOBJ([nl_langinfo])
+      fi
+      gl_LANGINFO_MODULE_INDICATOR([nl_langinfo])
+      gl_gnulib_enabled_nl_langinfo=true
+      func_gl_gnulib_m4code_langinfo
+      if test $HAVE_NL_LANGINFO = 0 || test $REPLACE_NL_LANGINFO = 1; then
+        func_gl_gnulib_m4code_localeconv
+      fi
+    fi
+  }
   func_gl_gnulib_m4code_open ()
   {
     if ! $gl_gnulib_enabled_open; then
@@ -583,6 +759,12 @@ AC_DEFUN
       gl_gnulib_enabled_6099e9737f757db36c47fa9d9f02e88c=true
     fi
   }
+  func_gl_gnulib_m4code_streq ()
+  {
+    if ! $gl_gnulib_enabled_streq; then
+      gl_gnulib_enabled_streq=true
+    fi
+  }
   func_gl_gnulib_m4code_strtoll ()
   {
     if ! $gl_gnulib_enabled_strtoll; then
@@ -595,6 +777,36 @@ AC_DEFUN
       gl_gnulib_enabled_strtoll=true
     fi
   }
+  func_gl_gnulib_m4code_wchar ()
+  {
+    if ! $gl_gnulib_enabled_wchar; then
+      gl_WCHAR_H
+      gl_gnulib_enabled_wchar=true
+    fi
+  }
+  func_gl_gnulib_m4code_wcrtomb ()
+  {
+    if ! $gl_gnulib_enabled_wcrtomb; then
+      gl_FUNC_WCRTOMB
+      if test $HAVE_WCRTOMB = 0 || test $REPLACE_WCRTOMB = 1; then
+        AC_LIBOBJ([wcrtomb])
+        gl_PREREQ_WCRTOMB
+      fi
+      gl_WCHAR_MODULE_INDICATOR([wcrtomb])
+      gl_gnulib_enabled_wcrtomb=true
+      if test $HAVE_WCRTOMB = 0 || test $REPLACE_WCRTOMB = 1; then
+        func_gl_gnulib_m4code_mbsinit
+      fi
+      func_gl_gnulib_m4code_wchar
+    fi
+  }
+  func_gl_gnulib_m4code_3dcce957eadc896e63ab5f137947b410 ()
+  {
+    if ! $gl_gnulib_enabled_3dcce957eadc896e63ab5f137947b410; then
+      gl_WCTYPE_H
+      gl_gnulib_enabled_3dcce957eadc896e63ab5f137947b410=true
+    fi
+  }
   func_gl_gnulib_m4code_682e609604ccaac6be382e4ee3a4eaec ()
   {
     if ! $gl_gnulib_enabled_682e609604ccaac6be382e4ee3a4eaec; then
@@ -649,6 +861,33 @@ AC_DEFUN
   if test $HAVE_READLINKAT = 0; then
     func_gl_gnulib_m4code_03e0aaad4cb89ca757653bd367a6ccb7
   fi
+  if test $ac_use_included_regex = yes; then
+    func_gl_gnulib_m4code_btowc
+  fi
+  if test $ac_use_included_regex = yes; then
+    func_gl_gnulib_m4code_37f71b604aa9c54446783d80f42fe547
+  fi
+  if test $ac_use_included_regex = yes; then
+    func_gl_gnulib_m4code_langinfo
+  fi
+  if test $ac_use_included_regex = yes; then
+    func_gl_gnulib_m4code_mbrtowc
+  fi
+  if test $ac_use_included_regex = yes; then
+    func_gl_gnulib_m4code_mbsinit
+  fi
+  if test $ac_use_included_regex = yes; then
+    func_gl_gnulib_m4code_nl_langinfo
+  fi
+  if test $ac_use_included_regex = yes; then
+    func_gl_gnulib_m4code_wchar
+  fi
+  if test $ac_use_included_regex = yes; then
+    func_gl_gnulib_m4code_wcrtomb
+  fi
+  if test $ac_use_included_regex = yes; then
+    func_gl_gnulib_m4code_3dcce957eadc896e63ab5f137947b410
+  fi
   if { test $HAVE_DECL_STRTOIMAX = 0 || test $REPLACE_STRTOIMAX = 1; } && test $ac_cv_type_long_long_int = yes; then
     func_gl_gnulib_m4code_strtoll
   fi
@@ -657,6 +896,8 @@ AC_DEFUN
   fi
   m4_pattern_allow([^gl_GNULIB_ENABLED_])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_260941c0e5dc67ec9e87d1fb321c300b], [$gl_gnulib_enabled_260941c0e5dc67ec9e87d1fb321c300b])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_btowc], [$gl_gnulib_enabled_btowc])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_37f71b604aa9c54446783d80f42fe547], [$gl_gnulib_enabled_37f71b604aa9c54446783d80f42fe547])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_cloexec], [$gl_gnulib_enabled_cloexec])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_dirfd], [$gl_gnulib_enabled_dirfd])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_dosname], [$gl_gnulib_enabled_dosname])
@@ -665,12 +906,25 @@ AC_DEFUN
   AM_CONDITIONAL([gl_GNULIB_ENABLED_getgroups], [$gl_gnulib_enabled_getgroups])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_be453cec5eecf5731a274f2de7f2db36], [$gl_gnulib_enabled_be453cec5eecf5731a274f2de7f2db36])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_a9786850e999ae65a836a6041e8e5ed1], [$gl_gnulib_enabled_a9786850e999ae65a836a6041e8e5ed1])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_30838f5439487421042f2225bed3af76], [$gl_gnulib_enabled_30838f5439487421042f2225bed3af76])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_langinfo], [$gl_gnulib_enabled_langinfo])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_localcharset], [$gl_gnulib_enabled_localcharset])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_locale], [$gl_gnulib_enabled_locale])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_localeconv], [$gl_gnulib_enabled_localeconv])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_2049e887c7e5308faad27b3f894bb8c9], [$gl_gnulib_enabled_2049e887c7e5308faad27b3f894bb8c9])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_mbrtowc], [$gl_gnulib_enabled_mbrtowc])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_mbsinit], [$gl_gnulib_enabled_mbsinit])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_mbtowc], [$gl_gnulib_enabled_mbtowc])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_5264294aa0a5557541b53c8c741f7f31], [$gl_gnulib_enabled_5264294aa0a5557541b53c8c741f7f31])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_nl_langinfo], [$gl_gnulib_enabled_nl_langinfo])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_open], [$gl_gnulib_enabled_open])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_03e0aaad4cb89ca757653bd367a6ccb7], [$gl_gnulib_enabled_03e0aaad4cb89ca757653bd367a6ccb7])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_6099e9737f757db36c47fa9d9f02e88c], [$gl_gnulib_enabled_6099e9737f757db36c47fa9d9f02e88c])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_streq], [$gl_gnulib_enabled_streq])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_strtoll], [$gl_gnulib_enabled_strtoll])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_wchar], [$gl_gnulib_enabled_wchar])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_wcrtomb], [$gl_gnulib_enabled_wcrtomb])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_3dcce957eadc896e63ab5f137947b410], [$gl_gnulib_enabled_3dcce957eadc896e63ab5f137947b410])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_682e609604ccaac6be382e4ee3a4eaec], [$gl_gnulib_enabled_682e609604ccaac6be382e4ee3a4eaec])
   # End of code from modules
   m4_ifval(gl_LIBSOURCES_LIST, [
@@ -828,6 +1082,7 @@ AC_DEFUN
   lib/at-func.c
   lib/binary-io.c
   lib/binary-io.h
+  lib/btowc.c
   lib/byteswap.in.h
   lib/c++defs.h
   lib/c-ctype.c
@@ -895,13 +1150,24 @@ AC_DEFUN
   lib/gettimeofday.c
   lib/gl_openssl.h
   lib/group-member.c
+  lib/hard-locale.c
+  lib/hard-locale.h
   lib/ignore-value.h
   lib/intprops.h
   lib/inttypes.in.h
+  lib/langinfo.in.h
   lib/limits.in.h
+  lib/localcharset.c
+  lib/localcharset.h
+  lib/locale.in.h
+  lib/localeconv.c
   lib/localtime-buffer.c
   lib/localtime-buffer.h
   lib/lstat.c
+  lib/mbrtowc.c
+  lib/mbsinit.c
+  lib/mbtowc-impl.h
+  lib/mbtowc.c
   lib/md5.c
   lib/md5.h
   lib/memrchr.c
@@ -909,6 +1175,7 @@ AC_DEFUN
   lib/mkostemp.c
   lib/mktime-internal.h
   lib/mktime.c
+  lib/nl_langinfo.c
   lib/nstrftime.c
   lib/open.c
   lib/openat-priv.h
@@ -921,6 +1188,12 @@ AC_DEFUN
   lib/qcopy-acl.c
   lib/readlink.c
   lib/readlinkat.c
+  lib/regcomp.c
+  lib/regex.c
+  lib/regex.h
+  lib/regex_internal.c
+  lib/regex_internal.h
+  lib/regexec.c
   lib/root-uid.h
   lib/set-permissions.c
   lib/sha1.c
@@ -941,6 +1214,7 @@ AC_DEFUN
   lib/stdio.in.h
   lib/stdlib.in.h
   lib/stpcpy.c
+  lib/streq.h
   lib/strftime.h
   lib/string.in.h
   lib/strtoimax.c
@@ -972,15 +1246,22 @@ AC_DEFUN
   lib/verify.h
   lib/vla.h
   lib/warn-on-use.h
+  lib/wchar.in.h
+  lib/wcrtomb.c
+  lib/wctype-h.c
+  lib/wctype.in.h
   lib/xalloc-oversized.h
   m4/00gnulib.m4
   m4/absolute-header.m4
   m4/acl.m4
   m4/alloca.m4
+  m4/btowc.m4
+  m4/builtin-expect.m4
   m4/byteswap.m4
   m4/c-strtod.m4
   m4/clock_time.m4
   m4/close-stream.m4
+  m4/codeset.m4
   m4/count-leading-zeros.m4
   m4/count-one-bits.m4
   m4/count-trailing-zeros.m4
@@ -988,6 +1269,7 @@ AC_DEFUN
   m4/dirent_h.m4
   m4/dirfd.m4
   m4/dup2.m4
+  m4/eealloc.m4
   m4/environ.m4
   m4/errno_h.m4
   m4/euidaccess.m4
@@ -1015,17 +1297,29 @@ AC_DEFUN
   m4/gettime.m4
   m4/gettimeofday.m4
   m4/gl-openssl.m4
+  m4/glibc21.m4
   m4/gnulib-common.m4
   m4/group-member.m4
   m4/include_next.m4
   m4/inttypes.m4
+  m4/langinfo_h.m4
   m4/largefile.m4
   m4/limits-h.m4
+  m4/localcharset.m4
+  m4/locale-fr.m4
+  m4/locale-ja.m4
+  m4/locale-zh.m4
+  m4/locale_h.m4
+  m4/localeconv.m4
   m4/localtime-buffer.m4
   m4/longlong.m4
   m4/lstat.m4
   m4/manywarnings-c++.m4
   m4/manywarnings.m4
+  m4/mbrtowc.m4
+  m4/mbsinit.m4
+  m4/mbstate_t.m4
+  m4/mbtowc.m4
   m4/md5.m4
   m4/memrchr.m4
   m4/minmax.m4
@@ -1033,6 +1327,7 @@ AC_DEFUN
   m4/mktime.m4
   m4/mode_t.m4
   m4/multiarch.m4
+  m4/nl_langinfo.m4
   m4/nocrash.m4
   m4/nstrftime.m4
   m4/off_t.m4
@@ -1044,6 +1339,7 @@ AC_DEFUN
   m4/putenv.m4
   m4/readlink.m4
   m4/readlinkat.m4
+  m4/regex.m4
   m4/sha1.m4
   m4/sha256.m4
   m4/sha512.m4
@@ -1084,6 +1380,9 @@ AC_DEFUN
   m4/vararrays.m4
   m4/warn-on-use.m4
   m4/warnings.m4
+  m4/wchar_h.m4
   m4/wchar_t.m4
+  m4/wcrtomb.m4
+  m4/wctype_h.m4
   m4/wint_t.m4
 ])
diff --git a/m4/langinfo_h.m4 b/m4/langinfo_h.m4
new file mode 100644
index 0000000000..de077c373d
--- /dev/null
+++ b/m4/langinfo_h.m4
@@ -0,0 +1,120 @@
+# langinfo_h.m4 serial 8
+dnl Copyright (C) 2009-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_LANGINFO_H],
+[
+  AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
+
+  dnl Persuade glibc-2.0.6 <langinfo.h> to define CODESET.
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  dnl <langinfo.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_CHECK_NEXT_HEADERS([langinfo.h])
+
+  dnl Determine whether <langinfo.h> exists. It is missing on mingw and BeOS.
+  HAVE_LANGINFO_CODESET=0
+  HAVE_LANGINFO_T_FMT_AMPM=0
+  HAVE_LANGINFO_ALTMON=0
+  HAVE_LANGINFO_ERA=0
+  HAVE_LANGINFO_YESEXPR=0
+  AC_CHECK_HEADERS_ONCE([langinfo.h])
+  if test $ac_cv_header_langinfo_h = yes; then
+    HAVE_LANGINFO_H=1
+    dnl Determine what <langinfo.h> defines. CODESET and ERA etc. are missing
+    dnl on OpenBSD 3.8. T_FMT_AMPM and YESEXPR, NOEXPR are missing on IRIX 5.3.
+    dnl ALTMON_* are missing on glibc 2.26 and many other systems.
+    AC_CACHE_CHECK([whether langinfo.h defines CODESET],
+      [gl_cv_header_langinfo_codeset],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+int a = CODESET;
+]])],
+         [gl_cv_header_langinfo_codeset=yes],
+         [gl_cv_header_langinfo_codeset=no])
+      ])
+    if test $gl_cv_header_langinfo_codeset = yes; then
+      HAVE_LANGINFO_CODESET=1
+    fi
+    AC_CACHE_CHECK([whether langinfo.h defines T_FMT_AMPM],
+      [gl_cv_header_langinfo_t_fmt_ampm],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+int a = T_FMT_AMPM;
+]])],
+         [gl_cv_header_langinfo_t_fmt_ampm=yes],
+         [gl_cv_header_langinfo_t_fmt_ampm=no])
+      ])
+    if test $gl_cv_header_langinfo_t_fmt_ampm = yes; then
+      HAVE_LANGINFO_T_FMT_AMPM=1
+    fi
+    AC_CACHE_CHECK([whether langinfo.h defines ALTMON_1],
+      [gl_cv_header_langinfo_altmon],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+int a = ALTMON_1;
+]])],
+         [gl_cv_header_langinfo_altmon=yes],
+         [gl_cv_header_langinfo_altmon=no])
+      ])
+    if test $gl_cv_header_langinfo_altmon = yes; then
+      HAVE_LANGINFO_ALTMON=1
+    fi
+    AC_CACHE_CHECK([whether langinfo.h defines ERA],
+      [gl_cv_header_langinfo_era],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+int a = ERA;
+]])],
+         [gl_cv_header_langinfo_era=yes],
+         [gl_cv_header_langinfo_era=no])
+      ])
+    if test $gl_cv_header_langinfo_era = yes; then
+      HAVE_LANGINFO_ERA=1
+    fi
+    AC_CACHE_CHECK([whether langinfo.h defines YESEXPR],
+      [gl_cv_header_langinfo_yesexpr],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+int a = YESEXPR;
+]])],
+         [gl_cv_header_langinfo_yesexpr=yes],
+         [gl_cv_header_langinfo_yesexpr=no])
+      ])
+    if test $gl_cv_header_langinfo_yesexpr = yes; then
+      HAVE_LANGINFO_YESEXPR=1
+    fi
+  else
+    HAVE_LANGINFO_H=0
+  fi
+  AC_SUBST([HAVE_LANGINFO_H])
+  AC_SUBST([HAVE_LANGINFO_CODESET])
+  AC_SUBST([HAVE_LANGINFO_T_FMT_AMPM])
+  AC_SUBST([HAVE_LANGINFO_ALTMON])
+  AC_SUBST([HAVE_LANGINFO_ERA])
+  AC_SUBST([HAVE_LANGINFO_YESEXPR])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <langinfo.h>
+    ]], [nl_langinfo])
+])
+
+AC_DEFUN([gl_LANGINFO_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_LANGINFO_H_DEFAULTS],
+[
+  GNULIB_NL_LANGINFO=0;  AC_SUBST([GNULIB_NL_LANGINFO])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_NL_LANGINFO=1;    AC_SUBST([HAVE_NL_LANGINFO])
+  REPLACE_NL_LANGINFO=0; AC_SUBST([REPLACE_NL_LANGINFO])
+])
diff --git a/m4/localcharset.m4 b/m4/localcharset.m4
new file mode 100644
index 0000000000..d38a2c9eb3
--- /dev/null
+++ b/m4/localcharset.m4
@@ -0,0 +1,11 @@
+# localcharset.m4 serial 8
+dnl Copyright (C) 2002, 2004, 2006, 2009-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_LOCALCHARSET],
+[
+  dnl Prerequisites of lib/localcharset.c.
+  AC_REQUIRE([AM_LANGINFO_CODESET])
+])
diff --git a/m4/locale-fr.m4 b/m4/locale-fr.m4
new file mode 100644
index 0000000000..a37a0d2024
--- /dev/null
+++ b/m4/locale-fr.m4
@@ -0,0 +1,257 @@
+# locale-fr.m4 serial 19
+dnl Copyright (C) 2003, 2005-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+dnl Determine the name of a french locale with traditional encoding.
+AC_DEFUN([gt_LOCALE_FR],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([AM_LANGINFO_CODESET])
+  AC_CACHE_CHECK([for a traditional french locale], [gt_cv_locale_fr], [
+    AC_LANG_CONFTEST([AC_LANG_SOURCE([
+changequote(,)dnl
+#include <locale.h>
+#include <time.h>
+#if HAVE_LANGINFO_CODESET
+# include <langinfo.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+struct tm t;
+char buf[16];
+int main () {
+  /* On BeOS and Haiku, locales are not implemented in libc.  Rather, libintl
+     imitates locale dependent behaviour by looking at the environment
+     variables, and all locales use the UTF-8 encoding.  */
+#if defined __BEOS__ || defined __HAIKU__
+  return 1;
+#else
+  /* Check whether the given locale name is recognized by the system.  */
+# if defined _WIN32 && !defined __CYGWIN__
+  /* On native Windows, setlocale(category, "") looks at the system settings,
+     not at the environment variables.  Also, when an encoding suffix such
+     as ".65001" or ".54936" is specified, it succeeds but sets the LC_CTYPE
+     category of the locale to "C".  */
+  if (setlocale (LC_ALL, getenv ("LC_ALL")) == NULL
+      || strcmp (setlocale (LC_CTYPE, NULL), "C") == 0)
+    return 1;
+# else
+  if (setlocale (LC_ALL, "") == NULL) return 1;
+# endif
+  /* Check whether nl_langinfo(CODESET) is nonempty and not "ASCII" or "646".
+     On Mac OS X 10.3.5 (Darwin 7.5) in the fr_FR locale, nl_langinfo(CODESET)
+     is empty, and the behaviour of Tcl 8.4 in this locale is not useful.
+     On OpenBSD 4.0, when an unsupported locale is specified, setlocale()
+     succeeds but then nl_langinfo(CODESET) is "646". In this situation,
+     some unit tests fail.
+     On MirBSD 10, when an unsupported locale is specified, setlocale()
+     succeeds but then nl_langinfo(CODESET) is "UTF-8".  */
+# if HAVE_LANGINFO_CODESET
+  {
+    const char *cs = nl_langinfo (CODESET);
+    if (cs[0] == '\0' || strcmp (cs, "ASCII") == 0 || strcmp (cs, "646") == 0
+        || strcmp (cs, "UTF-8") == 0)
+      return 1;
+  }
+# endif
+# ifdef __CYGWIN__
+  /* On Cygwin, avoid locale names without encoding suffix, because the
+     locale_charset() function relies on the encoding suffix.  Note that
+     LC_ALL is set on the command line.  */
+  if (strchr (getenv ("LC_ALL"), '.') == NULL) return 1;
+# endif
+  /* Check whether in the abbreviation of the second month, the second
+     character (should be U+00E9: LATIN SMALL LETTER E WITH ACUTE) is only
+     one byte long. This excludes the UTF-8 encoding.  */
+  t.tm_year = 1975 - 1900; t.tm_mon = 2 - 1; t.tm_mday = 4;
+  if (strftime (buf, sizeof (buf), "%b", &t) < 3 || buf[2] != 'v') return 1;
+# if !defined __BIONIC__ /* Bionic libc's 'struct lconv' is just a dummy.  */
+  /* Check whether the decimal separator is a comma.
+     On NetBSD 3.0 in the fr_FR.ISO8859-1 locale, localeconv()->decimal_point
+     are nl_langinfo(RADIXCHAR) are both ".".  */
+  if (localeconv () ->decimal_point[0] != ',') return 1;
+# endif
+  return 0;
+#endif
+}
+changequote([,])dnl
+      ])])
+    if AC_TRY_EVAL([ac_link]) && test -s conftest$ac_exeext; then
+      case "$host_os" in
+        # Handle native Windows specially, because there setlocale() interprets
+        # "ar" as "Arabic" or "Arabic_Saudi Arabia.1256",
+        # "fr" or "fra" as "French" or "French_France.1252",
+        # "ge"(!) or "deu"(!) as "German" or "German_Germany.1252",
+        # "ja" as "Japanese" or "Japanese_Japan.932",
+        # and similar.
+        mingw*)
+          # Test for the native Windows locale name.
+          if (LC_ALL=French_France.1252 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+            gt_cv_locale_fr=French_France.1252
+          else
+            # None found.
+            gt_cv_locale_fr=none
+          fi
+          ;;
+        *)
+          # Setting LC_ALL is not enough. Need to set LC_TIME to empty, because
+          # otherwise on Mac OS X 10.3.5 the LC_TIME=C from the beginning of the
+          # configure script would override the LC_ALL setting. Likewise for
+          # LC_CTYPE, which is also set at the beginning of the configure script.
+          # Test for the usual locale name.
+          if (LC_ALL=fr_FR LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+            gt_cv_locale_fr=fr_FR
+          else
+            # Test for the locale name with explicit encoding suffix.
+            if (LC_ALL=fr_FR.ISO-8859-1 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+              gt_cv_locale_fr=fr_FR.ISO-8859-1
+            else
+              # Test for the AIX, OSF/1, FreeBSD, NetBSD, OpenBSD locale name.
+              if (LC_ALL=fr_FR.ISO8859-1 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+                gt_cv_locale_fr=fr_FR.ISO8859-1
+              else
+                # Test for the HP-UX locale name.
+                if (LC_ALL=fr_FR.iso88591 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+                  gt_cv_locale_fr=fr_FR.iso88591
+                else
+                  # Test for the Solaris 7 locale name.
+                  if (LC_ALL=fr LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+                    gt_cv_locale_fr=fr
+                  else
+                    # None found.
+                    gt_cv_locale_fr=none
+                  fi
+                fi
+              fi
+            fi
+          fi
+          ;;
+      esac
+    fi
+    rm -fr conftest*
+  ])
+  LOCALE_FR=$gt_cv_locale_fr
+  AC_SUBST([LOCALE_FR])
+])
+
+dnl Determine the name of a french locale with UTF-8 encoding.
+AC_DEFUN([gt_LOCALE_FR_UTF8],
+[
+  AC_REQUIRE([AM_LANGINFO_CODESET])
+  AC_CACHE_CHECK([for a french Unicode locale], [gt_cv_locale_fr_utf8], [
+    AC_LANG_CONFTEST([AC_LANG_SOURCE([
+changequote(,)dnl
+#include <locale.h>
+#include <time.h>
+#if HAVE_LANGINFO_CODESET
+# include <langinfo.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+struct tm t;
+char buf[16];
+int main () {
+  /* On BeOS and Haiku, locales are not implemented in libc.  Rather, libintl
+     imitates locale dependent behaviour by looking at the environment
+     variables, and all locales use the UTF-8 encoding.  */
+#if !(defined __BEOS__ || defined __HAIKU__)
+  /* Check whether the given locale name is recognized by the system.  */
+# if defined _WIN32 && !defined __CYGWIN__
+  /* On native Windows, setlocale(category, "") looks at the system settings,
+     not at the environment variables.  Also, when an encoding suffix such
+     as ".65001" or ".54936" is specified, it succeeds but sets the LC_CTYPE
+     category of the locale to "C".  */
+  if (setlocale (LC_ALL, getenv ("LC_ALL")) == NULL
+      || strcmp (setlocale (LC_CTYPE, NULL), "C") == 0)
+    return 1;
+# else
+  if (setlocale (LC_ALL, "") == NULL) return 1;
+# endif
+  /* Check whether nl_langinfo(CODESET) is nonempty and not "ASCII" or "646".
+     On Mac OS X 10.3.5 (Darwin 7.5) in the fr_FR locale, nl_langinfo(CODESET)
+     is empty, and the behaviour of Tcl 8.4 in this locale is not useful.
+     On OpenBSD 4.0, when an unsupported locale is specified, setlocale()
+     succeeds but then nl_langinfo(CODESET) is "646". In this situation,
+     some unit tests fail.  */
+# if HAVE_LANGINFO_CODESET
+  {
+    const char *cs = nl_langinfo (CODESET);
+    if (cs[0] == '\0' || strcmp (cs, "ASCII") == 0 || strcmp (cs, "646") == 0)
+      return 1;
+  }
+# endif
+# ifdef __CYGWIN__
+  /* On Cygwin, avoid locale names without encoding suffix, because the
+     locale_charset() function relies on the encoding suffix.  Note that
+     LC_ALL is set on the command line.  */
+  if (strchr (getenv ("LC_ALL"), '.') == NULL) return 1;
+# endif
+  /* Check whether in the abbreviation of the second month, the second
+     character (should be U+00E9: LATIN SMALL LETTER E WITH ACUTE) is
+     two bytes long, with UTF-8 encoding.  */
+  t.tm_year = 1975 - 1900; t.tm_mon = 2 - 1; t.tm_mday = 4;
+  if (strftime (buf, sizeof (buf), "%b", &t) < 4
+      || buf[1] != (char) 0xc3 || buf[2] != (char) 0xa9 || buf[3] != 'v')
+    return 1;
+#endif
+#if !defined __BIONIC__ /* Bionic libc's 'struct lconv' is just a dummy.  */
+  /* Check whether the decimal separator is a comma.
+     On NetBSD 3.0 in the fr_FR.ISO8859-1 locale, localeconv()->decimal_point
+     are nl_langinfo(RADIXCHAR) are both ".".  */
+  if (localeconv () ->decimal_point[0] != ',') return 1;
+#endif
+  return 0;
+}
+changequote([,])dnl
+      ])])
+    if AC_TRY_EVAL([ac_link]) && test -s conftest$ac_exeext; then
+      case "$host_os" in
+        # Handle native Windows specially, because there setlocale() interprets
+        # "ar" as "Arabic" or "Arabic_Saudi Arabia.1256",
+        # "fr" or "fra" as "French" or "French_France.1252",
+        # "ge"(!) or "deu"(!) as "German" or "German_Germany.1252",
+        # "ja" as "Japanese" or "Japanese_Japan.932",
+        # and similar.
+        mingw*)
+          # Test for the hypothetical native Windows locale name.
+          if (LC_ALL=French_France.65001 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+            gt_cv_locale_fr_utf8=French_France.65001
+          else
+            # None found.
+            gt_cv_locale_fr_utf8=none
+          fi
+          ;;
+        *)
+          # Setting LC_ALL is not enough. Need to set LC_TIME to empty, because
+          # otherwise on Mac OS X 10.3.5 the LC_TIME=C from the beginning of the
+          # configure script would override the LC_ALL setting. Likewise for
+          # LC_CTYPE, which is also set at the beginning of the configure script.
+          # Test for the usual locale name.
+          if (LC_ALL=fr_FR LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+            gt_cv_locale_fr_utf8=fr_FR
+          else
+            # Test for the locale name with explicit encoding suffix.
+            if (LC_ALL=fr_FR.UTF-8 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+              gt_cv_locale_fr_utf8=fr_FR.UTF-8
+            else
+              # Test for the Solaris 7 locale name.
+              if (LC_ALL=fr.UTF-8 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+                gt_cv_locale_fr_utf8=fr.UTF-8
+              else
+                # None found.
+                gt_cv_locale_fr_utf8=none
+              fi
+            fi
+          fi
+          ;;
+      esac
+    fi
+    rm -fr conftest*
+  ])
+  LOCALE_FR_UTF8=$gt_cv_locale_fr_utf8
+  AC_SUBST([LOCALE_FR_UTF8])
+])
diff --git a/m4/locale-ja.m4 b/m4/locale-ja.m4
new file mode 100644
index 0000000000..9f1623191d
--- /dev/null
+++ b/m4/locale-ja.m4
@@ -0,0 +1,145 @@
+# locale-ja.m4 serial 14
+dnl Copyright (C) 2003, 2005-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+dnl Determine the name of a japanese locale with EUC-JP encoding.
+AC_DEFUN([gt_LOCALE_JA],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([AM_LANGINFO_CODESET])
+  AC_CACHE_CHECK([for a traditional japanese locale], [gt_cv_locale_ja], [
+    AC_LANG_CONFTEST([AC_LANG_SOURCE([
+changequote(,)dnl
+#include <locale.h>
+#include <time.h>
+#if HAVE_LANGINFO_CODESET
+# include <langinfo.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+struct tm t;
+char buf[16];
+int main ()
+{
+  /* On BeOS and Haiku, locales are not implemented in libc.  Rather, libintl
+     imitates locale dependent behaviour by looking at the environment
+     variables, and all locales use the UTF-8 encoding.  */
+#if defined __BEOS__ || defined __HAIKU__
+  return 1;
+#else
+  /* Check whether the given locale name is recognized by the system.  */
+# if defined _WIN32 && !defined __CYGWIN__
+  /* On native Windows, setlocale(category, "") looks at the system settings,
+     not at the environment variables.  Also, when an encoding suffix such
+     as ".65001" or ".54936" is specified, it succeeds but sets the LC_CTYPE
+     category of the locale to "C".  */
+  if (setlocale (LC_ALL, getenv ("LC_ALL")) == NULL
+      || strcmp (setlocale (LC_CTYPE, NULL), "C") == 0)
+    return 1;
+# else
+  if (setlocale (LC_ALL, "") == NULL) return 1;
+# endif
+  /* Check whether nl_langinfo(CODESET) is nonempty and not "ASCII" or "646".
+     On Mac OS X 10.3.5 (Darwin 7.5) in the fr_FR locale, nl_langinfo(CODESET)
+     is empty, and the behaviour of Tcl 8.4 in this locale is not useful.
+     On OpenBSD 4.0, when an unsupported locale is specified, setlocale()
+     succeeds but then nl_langinfo(CODESET) is "646". In this situation,
+     some unit tests fail.
+     On MirBSD 10, when an unsupported locale is specified, setlocale()
+     succeeds but then nl_langinfo(CODESET) is "UTF-8".  */
+# if HAVE_LANGINFO_CODESET
+  {
+    const char *cs = nl_langinfo (CODESET);
+    if (cs[0] == '\0' || strcmp (cs, "ASCII") == 0 || strcmp (cs, "646") == 0
+        || strcmp (cs, "UTF-8") == 0)
+      return 1;
+  }
+# endif
+# ifdef __CYGWIN__
+  /* On Cygwin, avoid locale names without encoding suffix, because the
+     locale_charset() function relies on the encoding suffix.  Note that
+     LC_ALL is set on the command line.  */
+  if (strchr (getenv ("LC_ALL"), '.') == NULL) return 1;
+# endif
+  /* Check whether MB_CUR_MAX is > 1.  This excludes the dysfunctional locales
+     on Cygwin 1.5.x.  */
+  if (MB_CUR_MAX == 1)
+    return 1;
+  /* Check whether in a month name, no byte in the range 0x80..0x9F occurs.
+     This excludes the UTF-8 encoding (except on MirBSD).  */
+  {
+    const char *p;
+    t.tm_year = 1975 - 1900; t.tm_mon = 2 - 1; t.tm_mday = 4;
+    if (strftime (buf, sizeof (buf), "%B", &t) < 2) return 1;
+    for (p = buf; *p != '\0'; p++)
+      if ((unsigned char) *p >= 0x80 && (unsigned char) *p < 0xa0)
+        return 1;
+  }
+  return 0;
+#endif
+}
+changequote([,])dnl
+      ])])
+    if AC_TRY_EVAL([ac_link]) && test -s conftest$ac_exeext; then
+      case "$host_os" in
+        # Handle native Windows specially, because there setlocale() interprets
+        # "ar" as "Arabic" or "Arabic_Saudi Arabia.1256",
+        # "fr" or "fra" as "French" or "French_France.1252",
+        # "ge"(!) or "deu"(!) as "German" or "German_Germany.1252",
+        # "ja" as "Japanese" or "Japanese_Japan.932",
+        # and similar.
+        mingw*)
+          # Note that on native Windows, the Japanese locale is
+          # Japanese_Japan.932, and CP932 is very different from EUC-JP, so we
+          # cannot use it here.
+          gt_cv_locale_ja=none
+          ;;
+        *)
+          # Setting LC_ALL is not enough. Need to set LC_TIME to empty, because
+          # otherwise on Mac OS X 10.3.5 the LC_TIME=C from the beginning of the
+          # configure script would override the LC_ALL setting. Likewise for
+          # LC_CTYPE, which is also set at the beginning of the configure script.
+          # Test for the AIX locale name.
+          if (LC_ALL=ja_JP LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+            gt_cv_locale_ja=ja_JP
+          else
+            # Test for the locale name with explicit encoding suffix.
+            if (LC_ALL=ja_JP.EUC-JP LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+              gt_cv_locale_ja=ja_JP.EUC-JP
+            else
+              # Test for the HP-UX, OSF/1, NetBSD locale name.
+              if (LC_ALL=ja_JP.eucJP LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+                gt_cv_locale_ja=ja_JP.eucJP
+              else
+                # Test for the IRIX, FreeBSD locale name.
+                if (LC_ALL=ja_JP.EUC LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+                  gt_cv_locale_ja=ja_JP.EUC
+                else
+                  # Test for the Solaris 7 locale name.
+                  if (LC_ALL=ja LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+                    gt_cv_locale_ja=ja
+                  else
+                    # Special test for NetBSD 1.6.
+                    if test -f /usr/share/locale/ja_JP.eucJP/LC_CTYPE; then
+                      gt_cv_locale_ja=ja_JP.eucJP
+                    else
+                      # None found.
+                      gt_cv_locale_ja=none
+                    fi
+                  fi
+                fi
+              fi
+            fi
+          fi
+          ;;
+      esac
+    fi
+    rm -fr conftest*
+  ])
+  LOCALE_JA=$gt_cv_locale_ja
+  AC_SUBST([LOCALE_JA])
+])
diff --git a/m4/locale-zh.m4 b/m4/locale-zh.m4
new file mode 100644
index 0000000000..cfb447f08d
--- /dev/null
+++ b/m4/locale-zh.m4
@@ -0,0 +1,139 @@
+# locale-zh.m4 serial 14
+dnl Copyright (C) 2003, 2005-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+
+dnl Determine the name of a chinese locale with GB18030 encoding.
+AC_DEFUN([gt_LOCALE_ZH_CN],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_REQUIRE([AM_LANGINFO_CODESET])
+  AC_CACHE_CHECK([for a transitional chinese locale], [gt_cv_locale_zh_CN], [
+    AC_LANG_CONFTEST([AC_LANG_SOURCE([
+changequote(,)dnl
+#include <locale.h>
+#include <stdlib.h>
+#include <time.h>
+#if HAVE_LANGINFO_CODESET
+# include <langinfo.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+struct tm t;
+char buf[16];
+int main ()
+{
+  /* On BeOS and Haiku, locales are not implemented in libc.  Rather, libintl
+     imitates locale dependent behaviour by looking at the environment
+     variables, and all locales use the UTF-8 encoding.  */
+#if defined __BEOS__ || defined __HAIKU__
+  return 1;
+#else
+  /* Check whether the given locale name is recognized by the system.  */
+# if defined _WIN32 && !defined __CYGWIN__
+  /* On native Windows, setlocale(category, "") looks at the system settings,
+     not at the environment variables.  Also, when an encoding suffix such
+     as ".65001" or ".54936" is specified, it succeeds but sets the LC_CTYPE
+     category of the locale to "C".  */
+  if (setlocale (LC_ALL, getenv ("LC_ALL")) == NULL
+      || strcmp (setlocale (LC_CTYPE, NULL), "C") == 0)
+    return 1;
+# else
+  if (setlocale (LC_ALL, "") == NULL) return 1;
+# endif
+  /* Check whether nl_langinfo(CODESET) is nonempty and not "ASCII" or "646".
+     On Mac OS X 10.3.5 (Darwin 7.5) in the fr_FR locale, nl_langinfo(CODESET)
+     is empty, and the behaviour of Tcl 8.4 in this locale is not useful.
+     On OpenBSD 4.0, when an unsupported locale is specified, setlocale()
+     succeeds but then nl_langinfo(CODESET) is "646". In this situation,
+     some unit tests fail.
+     On MirBSD 10, when an unsupported locale is specified, setlocale()
+     succeeds but then nl_langinfo(CODESET) is "UTF-8".  */
+# if HAVE_LANGINFO_CODESET
+  {
+    const char *cs = nl_langinfo (CODESET);
+    if (cs[0] == '\0' || strcmp (cs, "ASCII") == 0 || strcmp (cs, "646") == 0
+        || strcmp (cs, "UTF-8") == 0)
+      return 1;
+  }
+# endif
+# ifdef __CYGWIN__
+  /* On Cygwin, avoid locale names without encoding suffix, because the
+     locale_charset() function relies on the encoding suffix.  Note that
+     LC_ALL is set on the command line.  */
+  if (strchr (getenv ("LC_ALL"), '.') == NULL) return 1;
+# endif
+  /* Check whether in a month name, no byte in the range 0x80..0x9F occurs.
+     This excludes the UTF-8 encoding (except on MirBSD).  */
+  {
+    const char *p;
+    t.tm_year = 1975 - 1900; t.tm_mon = 2 - 1; t.tm_mday = 4;
+    if (strftime (buf, sizeof (buf), "%B", &t) < 2) return 1;
+    for (p = buf; *p != '\0'; p++)
+      if ((unsigned char) *p >= 0x80 && (unsigned char) *p < 0xa0)
+        return 1;
+  }
+  /* Check whether a typical GB18030 multibyte sequence is recognized as a
+     single wide character.  This excludes the GB2312 and GBK encodings.  */
+  if (mblen ("\203\062\332\066", 5) != 4)
+    return 1;
+  return 0;
+#endif
+}
+changequote([,])dnl
+      ])])
+    if AC_TRY_EVAL([ac_link]) && test -s conftest$ac_exeext; then
+      case "$host_os" in
+        # Handle native Windows specially, because there setlocale() interprets
+        # "ar" as "Arabic" or "Arabic_Saudi Arabia.1256",
+        # "fr" or "fra" as "French" or "French_France.1252",
+        # "ge"(!) or "deu"(!) as "German" or "German_Germany.1252",
+        # "ja" as "Japanese" or "Japanese_Japan.932",
+        # and similar.
+        mingw*)
+          # Test for the hypothetical native Windows locale name.
+          if (LC_ALL=Chinese_China.54936 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+            gt_cv_locale_zh_CN=Chinese_China.54936
+          else
+            # None found.
+            gt_cv_locale_zh_CN=none
+          fi
+          ;;
+        solaris2.8)
+          # On Solaris 8, the locales zh_CN.GB18030, zh_CN.GBK, zh.GBK are
+          # broken. One witness is the test case in gl_MBRTOWC_SANITYCHECK.
+          # Another witness is that "LC_ALL=zh_CN.GB18030 bash -c true" dumps core.
+          gt_cv_locale_zh_CN=none
+          ;;
+        *)
+          # Setting LC_ALL is not enough. Need to set LC_TIME to empty, because
+          # otherwise on Mac OS X 10.3.5 the LC_TIME=C from the beginning of the
+          # configure script would override the LC_ALL setting. Likewise for
+          # LC_CTYPE, which is also set at the beginning of the configure script.
+          # Test for the locale name without encoding suffix.
+          if (LC_ALL=zh_CN LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+            gt_cv_locale_zh_CN=zh_CN
+          else
+            # Test for the locale name with explicit encoding suffix.
+            if (LC_ALL=zh_CN.GB18030 LC_TIME= LC_CTYPE= ./conftest; exit) 2>/dev/null; then
+              gt_cv_locale_zh_CN=zh_CN.GB18030
+            else
+              # None found.
+              gt_cv_locale_zh_CN=none
+            fi
+          fi
+          ;;
+      esac
+    else
+      # If there was a link error, due to mblen(), the system is so old that
+      # it certainly doesn't have a chinese locale.
+      gt_cv_locale_zh_CN=none
+    fi
+    rm -fr conftest*
+  ])
+  LOCALE_ZH_CN=$gt_cv_locale_zh_CN
+  AC_SUBST([LOCALE_ZH_CN])
+])
diff --git a/m4/locale_h.m4 b/m4/locale_h.m4
new file mode 100644
index 0000000000..4bd9e574eb
--- /dev/null
+++ b/m4/locale_h.m4
@@ -0,0 +1,122 @@
+# locale_h.m4 serial 20
+dnl Copyright (C) 2007, 2009-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_LOCALE_H],
+[
+  dnl Use AC_REQUIRE here, so that the default behavior below is expanded
+  dnl once only, before all statements that occur in other macros.
+  AC_REQUIRE([gl_LOCALE_H_DEFAULTS])
+
+  dnl Persuade glibc <locale.h> to define locale_t and the int_p_*, int_n_*
+  dnl members of 'struct lconv'.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  dnl If <stddef.h> is replaced, then <locale.h> must also be replaced.
+  AC_REQUIRE([gl_STDDEF_H])
+
+  dnl Solaris 11.0 defines the int_p_*, int_n_* members of 'struct lconv'
+  dnl only if _LCONV_C99 is defined.
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    solaris*)
+      AC_DEFINE([_LCONV_C99], [1], [Define to 1 on Solaris.])
+      ;;
+  esac
+
+  AC_CACHE_CHECK([whether locale.h conforms to POSIX:2001],
+    [gl_cv_header_locale_h_posix2001],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <locale.h>
+            int x = LC_MESSAGES;
+            int y = sizeof (((struct lconv *) 0)->decimal_point);]],
+          [[]])],
+       [gl_cv_header_locale_h_posix2001=yes],
+       [gl_cv_header_locale_h_posix2001=no])])
+
+  dnl Check for <xlocale.h>.
+  AC_CHECK_HEADERS_ONCE([xlocale.h])
+  if test $ac_cv_header_xlocale_h = yes; then
+    HAVE_XLOCALE_H=1
+    dnl Check whether use of locale_t requires inclusion of <xlocale.h>,
+    dnl e.g. on Mac OS X 10.5. If <locale.h> does not define locale_t by
+    dnl itself, we assume that <xlocale.h> will do so.
+    AC_CACHE_CHECK([whether locale.h defines locale_t],
+      [gl_cv_header_locale_has_locale_t],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <locale.h>
+              locale_t x;]],
+            [[]])],
+         [gl_cv_header_locale_has_locale_t=yes],
+         [gl_cv_header_locale_has_locale_t=no])
+      ])
+    if test $gl_cv_header_locale_has_locale_t = yes; then
+      gl_cv_header_locale_h_needs_xlocale_h=no
+    else
+      gl_cv_header_locale_h_needs_xlocale_h=yes
+    fi
+  else
+    HAVE_XLOCALE_H=0
+    gl_cv_header_locale_h_needs_xlocale_h=no
+  fi
+  AC_SUBST([HAVE_XLOCALE_H])
+
+  dnl Check whether 'struct lconv' is complete.
+  dnl Bionic libc's 'struct lconv' is just a dummy.
+  dnl On OpenBSD 4.9, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 9, Cygwin 1.5.x,
+  dnl mingw, MSVC 9, it lacks the int_p_* and int_n_* members.
+  AC_CACHE_CHECK([whether struct lconv is properly defined],
+    [gl_cv_sys_struct_lconv_ok],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <locale.h>
+            struct lconv l;
+            int x = sizeof (l.decimal_point);
+            int y = sizeof (l.int_p_cs_precedes);]],
+          [[]])],
+       [gl_cv_sys_struct_lconv_ok=yes],
+       [gl_cv_sys_struct_lconv_ok=no])
+    ])
+  if test $gl_cv_sys_struct_lconv_ok = no; then
+    REPLACE_STRUCT_LCONV=1
+  fi
+
+  dnl <locale.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_NEXT_HEADERS([locale.h])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <locale.h>
+/* Some systems provide declarations in a non-standard header.  */
+#if HAVE_XLOCALE_H
+# include <xlocale.h>
+#endif
+    ]],
+    [setlocale duplocale])
+])
+
+AC_DEFUN([gl_LOCALE_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_LOCALE_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_LOCALE_H_DEFAULTS],
+[
+  GNULIB_LOCALECONV=0; AC_SUBST([GNULIB_LOCALECONV])
+  GNULIB_SETLOCALE=0;  AC_SUBST([GNULIB_SETLOCALE])
+  GNULIB_DUPLOCALE=0;  AC_SUBST([GNULIB_DUPLOCALE])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_DUPLOCALE=1;       AC_SUBST([HAVE_DUPLOCALE])
+  REPLACE_LOCALECONV=0;   AC_SUBST([REPLACE_LOCALECONV])
+  REPLACE_SETLOCALE=0;    AC_SUBST([REPLACE_SETLOCALE])
+  REPLACE_DUPLOCALE=0;    AC_SUBST([REPLACE_DUPLOCALE])
+  REPLACE_STRUCT_LCONV=0; AC_SUBST([REPLACE_STRUCT_LCONV])
+])
diff --git a/m4/localeconv.m4 b/m4/localeconv.m4
new file mode 100644
index 0000000000..517f398e41
--- /dev/null
+++ b/m4/localeconv.m4
@@ -0,0 +1,22 @@
+# localeconv.m4 serial 1
+dnl Copyright (C) 2012-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_LOCALECONV],
+[
+  AC_REQUIRE([gl_LOCALE_H_DEFAULTS])
+  AC_REQUIRE([gl_LOCALE_H])
+
+  if test $REPLACE_STRUCT_LCONV = 1; then
+    REPLACE_LOCALECONV=1
+  fi
+])
+
+# Prerequisites of lib/localeconv.c.
+AC_DEFUN([gl_PREREQ_LOCALECONV],
+[
+  AC_CHECK_MEMBERS([struct lconv.decimal_point], [], [],
+    [[#include <locale.h>]])
+])
diff --git a/m4/mbrtowc.m4 b/m4/mbrtowc.m4
new file mode 100644
index 0000000000..c706d04bca
--- /dev/null
+++ b/m4/mbrtowc.m4
@@ -0,0 +1,672 @@
+# mbrtowc.m4 serial 31  -*- coding: utf-8 -*-
+dnl Copyright (C) 2001-2002, 2004-2005, 2008-2018 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_MBRTOWC],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+
+  AC_REQUIRE([AC_TYPE_MBSTATE_T])
+  gl_MBSTATE_T_BROKEN
+
+  AC_CHECK_FUNCS_ONCE([mbrtowc])
+  if test $ac_cv_func_mbrtowc = no; then
+    HAVE_MBRTOWC=0
+    AC_CHECK_DECLS([mbrtowc],,, [[
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+]])
+    if test $ac_cv_have_decl_mbrtowc = yes; then
+      dnl On Minix 3.1.8, the system's <wchar.h> declares mbrtowc() although
+      dnl it does not have the function. Avoid a collision with gnulib's
+      dnl replacement.
+      REPLACE_MBRTOWC=1
+    fi
+  else
+    if test $REPLACE_MBSTATE_T = 1; then
+      REPLACE_MBRTOWC=1
+    else
+      gl_MBRTOWC_NULL_ARG1
+      gl_MBRTOWC_NULL_ARG2
+      gl_MBRTOWC_RETVAL
+      gl_MBRTOWC_NUL_RETVAL
+      gl_MBRTOWC_EMPTY_INPUT
+      gl_MBRTOWC_C_LOCALE
+      case "$gl_cv_func_mbrtowc_null_arg1" in
+        *yes) ;;
+        *) AC_DEFINE([MBRTOWC_NULL_ARG1_BUG], [1],
+             [Define if the mbrtowc function has the NULL pwc argument bug.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+      case "$gl_cv_func_mbrtowc_null_arg2" in
+        *yes) ;;
+        *) AC_DEFINE([MBRTOWC_NULL_ARG2_BUG], [1],
+             [Define if the mbrtowc function has the NULL string argument bug.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+      case "$gl_cv_func_mbrtowc_retval" in
+        *yes) ;;
+        *) AC_DEFINE([MBRTOWC_RETVAL_BUG], [1],
+             [Define if the mbrtowc function returns a wrong return value.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+      case "$gl_cv_func_mbrtowc_nul_retval" in
+        *yes) ;;
+        *) AC_DEFINE([MBRTOWC_NUL_RETVAL_BUG], [1],
+             [Define if the mbrtowc function does not return 0 for a NUL character.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+      case "$gl_cv_func_mbrtowc_empty_input" in
+        *yes) ;;
+        *) AC_DEFINE([MBRTOWC_EMPTY_INPUT_BUG], [1],
+             [Define if the mbrtowc function does not return (size_t) -2
+              for empty input.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+      case $gl_cv_C_locale_sans_EILSEQ in
+        *yes) ;;
+        *) AC_DEFINE([C_LOCALE_MAYBE_EILSEQ], [1],
+             [Define to 1 if the C locale may have encoding errors.])
+           REPLACE_MBRTOWC=1
+           ;;
+      esac
+    fi
+  fi
+])
+
+dnl Test whether mbsinit() and mbrtowc() need to be overridden in a way that
+dnl redefines the semantics of the given mbstate_t type.
+dnl Result is REPLACE_MBSTATE_T.
+dnl When this is set to 1, we replace both mbsinit() and mbrtowc(), in order to
+dnl avoid inconsistencies.
+
+AC_DEFUN([gl_MBSTATE_T_BROKEN],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+
+  AC_REQUIRE([AC_TYPE_MBSTATE_T])
+  AC_CHECK_FUNCS_ONCE([mbsinit])
+  AC_CHECK_FUNCS_ONCE([mbrtowc])
+  if test $ac_cv_func_mbsinit = yes && test $ac_cv_func_mbrtowc = yes; then
+    gl_MBRTOWC_INCOMPLETE_STATE
+    gl_MBRTOWC_SANITYCHECK
+    REPLACE_MBSTATE_T=0
+    case "$gl_cv_func_mbrtowc_incomplete_state" in
+      *yes) ;;
+      *) REPLACE_MBSTATE_T=1 ;;
+    esac
+    case "$gl_cv_func_mbrtowc_sanitycheck" in
+      *yes) ;;
+      *) REPLACE_MBSTATE_T=1 ;;
+    esac
+  else
+    REPLACE_MBSTATE_T=1
+  fi
+])
+
+dnl Test whether mbrtowc puts the state into non-initial state when parsing an
+dnl incomplete multibyte character.
+dnl Result is gl_cv_func_mbrtowc_incomplete_state.
+
+AC_DEFUN([gl_MBRTOWC_INCOMPLETE_STATE],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gt_LOCALE_JA])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc handles incomplete characters],
+    [gl_cv_func_mbrtowc_incomplete_state],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+                     # Guess no on AIX and OSF/1.
+        aix* | osf*) gl_cv_func_mbrtowc_incomplete_state="guessing no" ;;
+                     # Guess yes otherwise.
+        *)           gl_cv_func_mbrtowc_incomplete_state="guessing yes" ;;
+      esac
+changequote([,])dnl
+      if test $LOCALE_JA != none; then
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+int main ()
+{
+  if (setlocale (LC_ALL, "$LOCALE_JA") != NULL)
+    {
+      const char input[] = "B\217\253\344\217\251\316er"; /* "Büßer" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 1, 1, &state) == (size_t)(-2))
+        if (mbsinit (&state))
+          return 2;
+    }
+  return 0;
+}]])],
+          [gl_cv_func_mbrtowc_incomplete_state=yes],
+          [gl_cv_func_mbrtowc_incomplete_state=no],
+          [:])
+      fi
+    ])
+])
+
+dnl Test whether mbrtowc works not worse than mbtowc.
+dnl Result is gl_cv_func_mbrtowc_sanitycheck.
+
+AC_DEFUN([gl_MBRTOWC_SANITYCHECK],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gt_LOCALE_ZH_CN])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc works as well as mbtowc],
+    [gl_cv_func_mbrtowc_sanitycheck],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+                    # Guess no on Solaris 8.
+        solaris2.8) gl_cv_func_mbrtowc_sanitycheck="guessing no" ;;
+                    # Guess yes otherwise.
+        *)          gl_cv_func_mbrtowc_sanitycheck="guessing yes" ;;
+      esac
+changequote([,])dnl
+      if test $LOCALE_ZH_CN != none; then
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <stdlib.h>
+#include <string.h>
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+int main ()
+{
+  /* This fails on Solaris 8:
+     mbrtowc returns 2, and sets wc to 0x00F0.
+     mbtowc returns 4 (correct) and sets wc to 0x5EDC.  */
+  if (setlocale (LC_ALL, "$LOCALE_ZH_CN") != NULL)
+    {
+      char input[] = "B\250\271\201\060\211\070er"; /* "Büßer" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 3, 6, &state) != 4
+          && mbtowc (&wc, input + 3, 6) == 4)
+        return 2;
+    }
+  return 0;
+}]])],
+          [gl_cv_func_mbrtowc_sanitycheck=yes],
+          [gl_cv_func_mbrtowc_sanitycheck=no],
+          [:])
+      fi
+    ])
+])
+
+dnl Test whether mbrtowc supports a NULL pwc argument correctly.
+dnl Result is gl_cv_func_mbrtowc_null_arg1.
+
+AC_DEFUN([gl_MBRTOWC_NULL_ARG1],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gt_LOCALE_FR_UTF8])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc handles a NULL pwc argument],
+    [gl_cv_func_mbrtowc_null_arg1],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+                  # Guess no on Solaris.
+        solaris*) gl_cv_func_mbrtowc_null_arg1="guessing no" ;;
+                  # Guess yes otherwise.
+        *)        gl_cv_func_mbrtowc_null_arg1="guessing yes" ;;
+      esac
+changequote([,])dnl
+      if test $LOCALE_FR_UTF8 != none; then
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <stdlib.h>
+#include <string.h>
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+int main ()
+{
+  int result = 0;
+
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      char input[] = "\303\237er";
+      mbstate_t state;
+      wchar_t wc;
+      size_t ret;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      wc = (wchar_t) 0xBADFACE;
+      ret = mbrtowc (&wc, input, 5, &state);
+      if (ret != 2)
+        result |= 1;
+      if (!mbsinit (&state))
+        result |= 2;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      ret = mbrtowc (NULL, input, 5, &state);
+      if (ret != 2) /* Solaris 7 fails here: ret is -1.  */
+        result |= 4;
+      if (!mbsinit (&state))
+        result |= 8;
+    }
+  return result;
+}]])],
+          [gl_cv_func_mbrtowc_null_arg1=yes],
+          [gl_cv_func_mbrtowc_null_arg1=no],
+          [:])
+      fi
+    ])
+])
+
+dnl Test whether mbrtowc supports a NULL string argument correctly.
+dnl Result is gl_cv_func_mbrtowc_null_arg2.
+
+AC_DEFUN([gl_MBRTOWC_NULL_ARG2],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gt_LOCALE_FR_UTF8])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc handles a NULL string argument],
+    [gl_cv_func_mbrtowc_null_arg2],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+              # Guess no on OSF/1.
+        osf*) gl_cv_func_mbrtowc_null_arg2="guessing no" ;;
+              # Guess yes otherwise.
+        *)    gl_cv_func_mbrtowc_null_arg2="guessing yes" ;;
+      esac
+changequote([,])dnl
+      if test $LOCALE_FR_UTF8 != none; then
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+int main ()
+{
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      mbstate_t state;
+      wchar_t wc;
+      int ret;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      wc = (wchar_t) 0xBADFACE;
+      mbrtowc (&wc, NULL, 5, &state);
+      /* Check that wc was not modified.  */
+      if (wc != (wchar_t) 0xBADFACE)
+        return 2;
+    }
+  return 0;
+}]])],
+          [gl_cv_func_mbrtowc_null_arg2=yes],
+          [gl_cv_func_mbrtowc_null_arg2=no],
+          [:])
+      fi
+    ])
+])
+
+dnl Test whether mbrtowc, when parsing the end of a multibyte character,
+dnl correctly returns the number of bytes that were needed to complete the
+dnl character (not the total number of bytes of the multibyte character).
+dnl Result is gl_cv_func_mbrtowc_retval.
+
+AC_DEFUN([gl_MBRTOWC_RETVAL],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gt_LOCALE_FR_UTF8])
+  AC_REQUIRE([gt_LOCALE_JA])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CACHE_CHECK([whether mbrtowc has a correct return value],
+    [gl_cv_func_mbrtowc_retval],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+                                   # Guess no on HP-UX, Solaris, native Windows.
+        hpux* | solaris* | mingw*) gl_cv_func_mbrtowc_retval="guessing no" ;;
+                                   # Guess yes otherwise.
+        *)                         gl_cv_func_mbrtowc_retval="guessing yes" ;;
+      esac
+changequote([,])dnl
+      if test $LOCALE_FR_UTF8 != none || test $LOCALE_JA != none \
+         || { case "$host_os" in mingw*) true;; *) false;; esac; }; then
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+int main ()
+{
+  int result = 0;
+  int found_some_locale = 0;
+  /* This fails on Solaris.  */
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      char input[] = "B\303\274\303\237er"; /* "Büßer" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 1, 1, &state) == (size_t)(-2))
+        {
+          input[1] = '\0';
+          if (mbrtowc (&wc, input + 2, 5, &state) != 1)
+            result |= 1;
+        }
+      found_some_locale = 1;
+    }
+  /* This fails on HP-UX 11.11.  */
+  if (setlocale (LC_ALL, "$LOCALE_JA") != NULL)
+    {
+      char input[] = "B\217\253\344\217\251\316er"; /* "Büßer" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 1, 1, &state) == (size_t)(-2))
+        {
+          input[1] = '\0';
+          if (mbrtowc (&wc, input + 2, 5, &state) != 2)
+            result |= 2;
+        }
+      found_some_locale = 1;
+    }
+  /* This fails on native Windows.  */
+  if (setlocale (LC_ALL, "Japanese_Japan.932") != NULL)
+    {
+      char input[] = "<\223\372\226\173\214\352>"; /* "<日本語>" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 3, 1, &state) == (size_t)(-2))
+        {
+          input[3] = '\0';
+          if (mbrtowc (&wc, input + 4, 4, &state) != 1)
+            result |= 4;
+        }
+      found_some_locale = 1;
+    }
+  if (setlocale (LC_ALL, "Chinese_Taiwan.950") != NULL)
+    {
+      char input[] = "<\244\351\245\273\273\171>"; /* "<日本語>" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 3, 1, &state) == (size_t)(-2))
+        {
+          input[3] = '\0';
+          if (mbrtowc (&wc, input + 4, 4, &state) != 1)
+            result |= 8;
+        }
+      found_some_locale = 1;
+    }
+  if (setlocale (LC_ALL, "Chinese_China.936") != NULL)
+    {
+      char input[] = "<\310\325\261\276\325\132>"; /* "<日本語>" */
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, input + 3, 1, &state) == (size_t)(-2))
+        {
+          input[3] = '\0';
+          if (mbrtowc (&wc, input + 4, 4, &state) != 1)
+            result |= 16;
+        }
+      found_some_locale = 1;
+    }
+  return (found_some_locale ? result : 77);
+}]])],
+          [gl_cv_func_mbrtowc_retval=yes],
+          [if test $? != 77; then
+             gl_cv_func_mbrtowc_retval=no
+           fi
+          ],
+          [:])
+      fi
+    ])
+])
+
+dnl Test whether mbrtowc, when parsing a NUL character, correctly returns 0.
+dnl Result is gl_cv_func_mbrtowc_nul_retval.
+
+AC_DEFUN([gl_MBRTOWC_NUL_RETVAL],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gt_LOCALE_ZH_CN])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc returns 0 when parsing a NUL character],
+    [gl_cv_func_mbrtowc_nul_retval],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+                       # Guess no on Solaris 8 and 9.
+        solaris2.[89]) gl_cv_func_mbrtowc_nul_retval="guessing no" ;;
+                       # Guess yes otherwise.
+        *)             gl_cv_func_mbrtowc_nul_retval="guessing yes" ;;
+      esac
+changequote([,])dnl
+      if test $LOCALE_ZH_CN != none; then
+        AC_RUN_IFELSE(
+          [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+int main ()
+{
+  /* This fails on Solaris 8 and 9.  */
+  if (setlocale (LC_ALL, "$LOCALE_ZH_CN") != NULL)
+    {
+      mbstate_t state;
+      wchar_t wc;
+
+      memset (&state, '\0', sizeof (mbstate_t));
+      if (mbrtowc (&wc, "", 1, &state) != 0)
+        return 2;
+    }
+  return 0;
+}]])],
+          [gl_cv_func_mbrtowc_nul_retval=yes],
+          [gl_cv_func_mbrtowc_nul_retval=no],
+          [:])
+      fi
+    ])
+])
+
+dnl Test whether mbrtowc returns the correct value on empty input.
+
+AC_DEFUN([gl_MBRTOWC_EMPTY_INPUT],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether mbrtowc works on empty input],
+    [gl_cv_func_mbrtowc_empty_input],
+    [
+      dnl Initial guess, used when cross-compiling or when no suitable locale
+      dnl is present.
+changequote(,)dnl
+      case "$host_os" in
+                              # Guess no on AIX and glibc systems.
+        aix* | *-gnu* | gnu*) gl_cv_func_mbrtowc_empty_input="guessing no" ;;
+                              # Guess yes on native Windows.
+        mingw*)               gl_cv_func_mbrtowc_empty_input="guessing yes" ;;
+        *)                    gl_cv_func_mbrtowc_empty_input="guessing yes" ;;
+      esac
+changequote([,])dnl
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+           #include <wchar.h>
+           static wchar_t wc;
+           static mbstate_t mbs;
+           int
+           main (void)
+           {
+             return mbrtowc (&wc, "", 0, &mbs) != (size_t) -2;
+           }]])],
+        [gl_cv_func_mbrtowc_empty_input=yes],
+        [gl_cv_func_mbrtowc_empty_input=no],
+        [:])
+    ])
+])
+
+dnl Test whether mbrtowc reports encoding errors in the C locale.
+dnl Although POSIX was never intended to allow this, the GNU C Library
+dnl and other implementations do it.  See:
+dnl https://sourceware.org/bugzilla/show_bug.cgi?id=19932
+
+AC_DEFUN([gl_MBRTOWC_C_LOCALE],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether the C locale is free of encoding errors],
+    [gl_cv_C_locale_sans_EILSEQ],
+    [
+     dnl Initial guess, used when cross-compiling or when no suitable locale
+     dnl is present.
+     gl_cv_C_locale_sans_EILSEQ="guessing no"
+
+     AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <limits.h>
+            #include <locale.h>
+            #include <wchar.h>
+          ]], [[
+            int i;
+            char *locale = setlocale (LC_ALL, "C");
+            if (! locale)
+              return 2;
+            for (i = CHAR_MIN; i <= CHAR_MAX; i++)
+              {
+                char c = i;
+                wchar_t wc;
+                mbstate_t mbs = { 0, };
+                size_t ss = mbrtowc (&wc, &c, 1, &mbs);
+                if (1 < ss)
+                  return 3;
+              }
+            return 0;
+          ]])],
+      [gl_cv_C_locale_sans_EILSEQ=yes],
+      [gl_cv_C_locale_sans_EILSEQ=no],
+      [case "$host_os" in
+                 # Guess yes on native Windows.
+         mingw*) gl_cv_C_locale_sans_EILSEQ="guessing yes" ;;
+       esac
+      ])
+    ])
+])
+
+# Prerequisites of lib/mbrtowc.c.
+AC_DEFUN([gl_PREREQ_MBRTOWC], [
+  AC_REQUIRE([AC_C_INLINE])
+  :
+])
+
+
+dnl From Paul Eggert
+
+dnl This is an override of an autoconf macro.
+
+AC_DEFUN([AC_FUNC_MBRTOWC],
+[
+  dnl Same as AC_FUNC_MBRTOWC in autoconf-2.60.
+  AC_CACHE_CHECK([whether mbrtowc and mbstate_t are properly declared],
+    [gl_cv_func_mbrtowc],
+    [AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+            [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
+                 included before <wchar.h>.
+                 BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
+                 must be included before <wchar.h>.  */
+              #include <stddef.h>
+              #include <stdio.h>
+              #include <time.h>
+              #include <wchar.h>]],
+            [[wchar_t wc;
+              char const s[] = "";
+              size_t n = 1;
+              mbstate_t state;
+              return ! (sizeof state && (mbrtowc) (&wc, s, n, &state));]])],
+       [gl_cv_func_mbrtowc=yes],
+       [gl_cv_func_mbrtowc=no])])
+  if test $gl_cv_func_mbrtowc = yes; then
+    AC_DEFINE([HAVE_MBRTOWC], [1],
+      [Define to 1 if mbrtowc and mbstate_t are properly declared.])
+  fi
+])
diff --git a/m4/mbsinit.m4 b/m4/mbsinit.m4
new file mode 100644
index 0000000000..5cba3df0f0
--- /dev/null
+++ b/m4/mbsinit.m4
@@ -0,0 +1,51 @@
+# mbsinit.m4 serial 8
+dnl Copyright (C) 2008, 2010-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_MBSINIT],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  AC_REQUIRE([AC_TYPE_MBSTATE_T])
+  gl_MBSTATE_T_BROKEN
+
+  AC_CHECK_FUNCS_ONCE([mbsinit])
+  if test $ac_cv_func_mbsinit = no; then
+    HAVE_MBSINIT=0
+    AC_CHECK_DECLS([mbsinit],,, [[
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+]])
+    if test $ac_cv_have_decl_mbsinit = yes; then
+      dnl On Minix 3.1.8, the system's <wchar.h> declares mbsinit() although
+      dnl it does not have the function. Avoid a collision with gnulib's
+      dnl replacement.
+      REPLACE_MBSINIT=1
+    fi
+  else
+    if test $REPLACE_MBSTATE_T = 1; then
+      REPLACE_MBSINIT=1
+    else
+      dnl On mingw, mbsinit() always returns 1, which is inappropriate for
+      dnl states produced by mbrtowc() for an incomplete multibyte character
+      dnl in multibyte locales.
+      case "$host_os" in
+        mingw*) REPLACE_MBSINIT=1 ;;
+      esac
+    fi
+  fi
+])
+
+# Prerequisites of lib/mbsinit.c.
+AC_DEFUN([gl_PREREQ_MBSINIT], [
+  :
+])
diff --git a/m4/mbstate_t.m4 b/m4/mbstate_t.m4
new file mode 100644
index 0000000000..004aa0d17c
--- /dev/null
+++ b/m4/mbstate_t.m4
@@ -0,0 +1,41 @@
+# mbstate_t.m4 serial 13
+dnl Copyright (C) 2000-2002, 2008-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# From Paul Eggert.
+
+# BeOS 5 has <wchar.h> but does not define mbstate_t,
+# so you can't declare an object of that type.
+# Check for this incompatibility with Standard C.
+
+# AC_TYPE_MBSTATE_T
+# -----------------
+AC_DEFUN([AC_TYPE_MBSTATE_T],
+[
+   AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) dnl for HP-UX 11.11
+
+   AC_CACHE_CHECK([for mbstate_t], [ac_cv_type_mbstate_t],
+     [AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM(
+           [AC_INCLUDES_DEFAULT[
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>]],
+           [[mbstate_t x; return sizeof x;]])],
+        [ac_cv_type_mbstate_t=yes],
+        [ac_cv_type_mbstate_t=no])])
+   if test $ac_cv_type_mbstate_t = yes; then
+     AC_DEFINE([HAVE_MBSTATE_T], [1],
+               [Define to 1 if <wchar.h> declares mbstate_t.])
+   else
+     AC_DEFINE([mbstate_t], [int],
+               [Define to a type if <wchar.h> does not define.])
+   fi
+])
diff --git a/m4/mbtowc.m4 b/m4/mbtowc.m4
new file mode 100644
index 0000000000..ecac6a2650
--- /dev/null
+++ b/m4/mbtowc.m4
@@ -0,0 +1,19 @@
+# mbtowc.m4 serial 2
+dnl Copyright (C) 2011-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_MBTOWC],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+
+  if false; then
+    REPLACE_MBTOWC=1
+  fi
+])
+
+# Prerequisites of lib/mbtowc.c.
+AC_DEFUN([gl_PREREQ_MBTOWC], [
+  :
+])
diff --git a/m4/nl_langinfo.m4 b/m4/nl_langinfo.m4
new file mode 100644
index 0000000000..82d475024a
--- /dev/null
+++ b/m4/nl_langinfo.m4
@@ -0,0 +1,53 @@
+# nl_langinfo.m4 serial 6
+dnl Copyright (C) 2009-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_NL_LANGINFO],
+[
+  AC_REQUIRE([gl_LANGINFO_H_DEFAULTS])
+  AC_REQUIRE([gl_LANGINFO_H])
+  AC_CHECK_FUNCS_ONCE([nl_langinfo])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  if test $ac_cv_func_nl_langinfo = yes; then
+    # On Irix 6.5, YESEXPR is defined, but nl_langinfo(YESEXPR) is broken.
+    AC_CACHE_CHECK([whether YESEXPR works],
+      [gl_cv_func_nl_langinfo_yesexpr_works],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM([[#include <langinfo.h>
+]], [[return !*nl_langinfo(YESEXPR);
+]])],
+         [gl_cv_func_nl_langinfo_yesexpr_works=yes],
+         [gl_cv_func_nl_langinfo_yesexpr_works=no],
+         [
+         case "$host_os" in
+                   # Guess no on irix systems.
+           irix*)  gl_cv_func_nl_langinfo_yesexpr_works="guessing no";;
+                   # Guess yes elsewhere.
+           *)      gl_cv_func_nl_langinfo_yesexpr_works="guessing yes";;
+         esac
+         ])
+      ])
+    case $gl_cv_func_nl_langinfo_yesexpr_works in
+      *yes) FUNC_NL_LANGINFO_YESEXPR_WORKS=1 ;;
+      *)    FUNC_NL_LANGINFO_YESEXPR_WORKS=0 ;;
+    esac
+    AC_DEFINE_UNQUOTED([FUNC_NL_LANGINFO_YESEXPR_WORKS],
+      [$FUNC_NL_LANGINFO_YESEXPR_WORKS],
+      [Define to 1 if nl_langinfo (YESEXPR) returns a non-empty string.])
+    if test $HAVE_LANGINFO_CODESET = 1 \
+       && test $HAVE_LANGINFO_T_FMT_AMPM = 1 \
+       && test $HAVE_LANGINFO_ALTMON = 1 \
+       && test $HAVE_LANGINFO_ERA = 1 \
+       && test $FUNC_NL_LANGINFO_YESEXPR_WORKS = 1; then
+      :
+    else
+      REPLACE_NL_LANGINFO=1
+      AC_DEFINE([REPLACE_NL_LANGINFO], [1],
+        [Define if nl_langinfo exists but is overridden by gnulib.])
+    fi
+  else
+    HAVE_NL_LANGINFO=0
+  fi
+])
diff --git a/m4/regex.m4 b/m4/regex.m4
new file mode 100644
index 0000000000..055d71b5aa
--- /dev/null
+++ b/m4/regex.m4
@@ -0,0 +1,300 @@
+# serial 67
+
+# Copyright (C) 1996-2001, 2003-2018 Free Software Foundation, Inc.
+#
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl Initially derived from code in GNU grep.
+dnl Mostly written by Jim Meyering.
+
+AC_PREREQ([2.50])
+
+AC_DEFUN([gl_REGEX],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_ARG_WITH([included-regex],
+    [AS_HELP_STRING([--without-included-regex],
+                    [don't compile regex; this is the default on systems
+                     with recent-enough versions of the GNU C Library
+                     (use with caution on other systems).])])
+
+  case $with_included_regex in #(
+  yes|no) ac_use_included_regex=$with_included_regex
+        ;;
+  '')
+    # If the system regex support is good enough that it passes the
+    # following run test, then default to *not* using the included regex.c.
+    # If cross compiling, assume the test would fail and use the included
+    # regex.c.
+    AC_CHECK_DECLS_ONCE([alarm])
+    AC_CHECK_HEADERS_ONCE([malloc.h])
+    AC_CACHE_CHECK([for working re_compile_pattern],
+                   [gl_cv_func_re_compile_pattern_working],
+      [AC_RUN_IFELSE(
+        [AC_LANG_PROGRAM(
+          [[#include <regex.h>
+
+            #include <locale.h>
+            #include <limits.h>
+            #include <string.h>
+
+            #if defined M_CHECK_ACTION || HAVE_DECL_ALARM
+            # include <signal.h>
+            # include <unistd.h>
+            #endif
+
+            #if HAVE_MALLOC_H
+            # include <malloc.h>
+            #endif
+
+            #ifdef M_CHECK_ACTION
+            /* Exit with distinguishable exit code.  */
+            static void sigabrt_no_core (int sig) { raise (SIGTERM); }
+            #endif
+          ]],
+          [[int result = 0;
+            static struct re_pattern_buffer regex;
+            unsigned char folded_chars[UCHAR_MAX + 1];
+            int i;
+            const char *s;
+            struct re_registers regs;
+
+            /* Some builds of glibc go into an infinite loop on this
+               test.  Use alarm to force death, and mallopt to avoid
+               malloc recursion in diagnosing the corrupted heap. */
+#if HAVE_DECL_ALARM
+            signal (SIGALRM, SIG_DFL);
+            alarm (2);
+#endif
+#ifdef M_CHECK_ACTION
+            signal (SIGABRT, sigabrt_no_core);
+            mallopt (M_CHECK_ACTION, 2);
+#endif
+
+            if (setlocale (LC_ALL, "en_US.UTF-8"))
+              {
+                {
+                  /* https://sourceware.org/ml/libc-hacker/2006-09/msg00008.html
+                     This test needs valgrind to catch the bug on Debian
+                     GNU/Linux 3.1 x86, but it might catch the bug better
+                     on other platforms and it shouldn't hurt to try the
+                     test here.  */
+                  static char const pat[] = "insert into";
+                  static char const data[] =
+                    "\xFF\0\x12\xA2\xAA\xC4\xB1,K\x12\xC4\xB1*\xACK";
+                  re_set_syntax (RE_SYNTAX_GREP | RE_HAT_LISTS_NOT_NEWLINE
+                                 | RE_ICASE);
+                  memset (&regex, 0, sizeof regex);
+                  s = re_compile_pattern (pat, sizeof pat - 1, &regex);
+                  if (s)
+                    result |= 1;
+                  else if (re_search (&regex, data, sizeof data - 1,
+                                      0, sizeof data - 1, &regs)
+                           != -1)
+                    result |= 1;
+                  regfree (&regex);
+                }
+
+                {
+                  /* This test is from glibc bug 15078.
+                     The test case is from Andreas Schwab in
+                     <https://sourceware.org/ml/libc-alpha/2013-01/msg00967.html>.
+                     */
+                  static char const pat[] = "[^x]x";
+                  static char const data[] =
+                    /* <U1000><U103B><U103D><U1014><U103A><U102F><U1015><U103A> */
+                    "\xe1\x80\x80"
+                    "\xe1\x80\xbb"
+                    "\xe1\x80\xbd"
+                    "\xe1\x80\x94"
+                    "\xe1\x80\xba"
+                    "\xe1\x80\xaf"
+                    "\xe1\x80\x95"
+                    "\xe1\x80\xba"
+                    "x";
+                  re_set_syntax (0);
+                  memset (&regex, 0, sizeof regex);
+                  s = re_compile_pattern (pat, sizeof pat - 1, &regex);
+                  if (s)
+                    result |= 1;
+                  else
+                    {
+                      i = re_search (&regex, data, sizeof data - 1,
+                                     0, sizeof data - 1, 0);
+                      if (i != 0 && i != 21)
+                        result |= 1;
+                    }
+                  regfree (&regex);
+                }
+
+                if (! setlocale (LC_ALL, "C"))
+                  return 1;
+              }
+
+            /* This test is from glibc bug 3957, reported by Andrew Mackey.  */
+            re_set_syntax (RE_SYNTAX_EGREP | RE_HAT_LISTS_NOT_NEWLINE);
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("a[^x]b", 6, &regex);
+            if (s)
+              result |= 2;
+            /* This should fail, but succeeds for glibc-2.5.  */
+            else if (re_search (&regex, "a\nb", 3, 0, 3, &regs) != -1)
+              result |= 2;
+
+            /* This regular expression is from Spencer ere test number 75
+               in grep-2.3.  */
+            re_set_syntax (RE_SYNTAX_POSIX_EGREP);
+            memset (&regex, 0, sizeof regex);
+            for (i = 0; i <= UCHAR_MAX; i++)
+              folded_chars[i] = i;
+            regex.translate = folded_chars;
+            s = re_compile_pattern ("a[[:@:>@:]]b\n", 11, &regex);
+            /* This should fail with _Invalid character class name_ error.  */
+            if (!s)
+              result |= 4;
+
+            /* Ensure that [b-a] is diagnosed as invalid, when
+               using RE_NO_EMPTY_RANGES. */
+            re_set_syntax (RE_SYNTAX_POSIX_EGREP | RE_NO_EMPTY_RANGES);
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("a[b-a]", 6, &regex);
+            if (s == 0)
+              result |= 8;
+
+            /* This should succeed, but does not for glibc-2.1.3.  */
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("{1", 2, &regex);
+            if (s)
+              result |= 8;
+
+            /* The following example is derived from a problem report
+               against gawk from Jorge Stolfi <[email-masked]>.  */
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("[an\371]*n", 7, &regex);
+            if (s)
+              result |= 8;
+            /* This should match, but does not for glibc-2.2.1.  */
+            else if (re_match (&regex, "an", 2, 0, &regs) != 2)
+              result |= 8;
+
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("x", 1, &regex);
+            if (s)
+              result |= 8;
+            /* glibc-2.2.93 does not work with a negative RANGE argument.  */
+            else if (re_search (&regex, "wxy", 3, 2, -2, &regs) != 1)
+              result |= 8;
+
+            /* The version of regex.c in older versions of gnulib
+               ignored RE_ICASE.  Detect that problem too.  */
+            re_set_syntax (RE_SYNTAX_EMACS | RE_ICASE);
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("x", 1, &regex);
+            if (s)
+              result |= 16;
+            else if (re_search (&regex, "WXY", 3, 0, 3, &regs) < 0)
+              result |= 16;
+
+            /* Catch a bug reported by Vin Shelton in
+               https://lists.gnu.org/r/bug-coreutils/2007-06/msg00089.html
+               */
+            re_set_syntax (RE_SYNTAX_POSIX_BASIC
+                           & ~RE_CONTEXT_INVALID_DUP
+                           & ~RE_NO_EMPTY_RANGES);
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("[[:alnum:]_-]\\\\+$", 16, &regex);
+            if (s)
+              result |= 32;
+
+            /* REG_STARTEND was added to glibc on 2004-01-15.
+               Reject older versions.  */
+            if (! REG_STARTEND)
+              result |= 64;
+
+#if 0
+            /* It would be nice to reject hosts whose regoff_t values are too
+               narrow (including glibc on hosts with 64-bit ptrdiff_t and
+               32-bit int), but we should wait until glibc implements this
+               feature.  Otherwise, support for equivalence classes and
+               multibyte collation symbols would always be broken except
+               when compiling --without-included-regex.   */
+            if (sizeof (regoff_t) < sizeof (ptrdiff_t)
+                || sizeof (regoff_t) < sizeof (ssize_t))
+              result |= 64;
+#endif
+
+            return result;
+          ]])],
+        [gl_cv_func_re_compile_pattern_working=yes],
+        [gl_cv_func_re_compile_pattern_working=no],
+        [case "$host_os" in
+                   # Guess no on native Windows.
+           mingw*) gl_cv_func_re_compile_pattern_working="guessing no" ;;
+                   # Otherwise, assume it is not working.
+           *)      gl_cv_func_re_compile_pattern_working="guessing no" ;;
+         esac
+        ])
+      ])
+    case "$gl_cv_func_re_compile_pattern_working" in #(
+      *yes) ac_use_included_regex=no;; #(
+      *no) ac_use_included_regex=yes;;
+    esac
+    ;;
+  *) AC_MSG_ERROR([Invalid value for --with-included-regex: $with_included_regex])
+    ;;
+  esac
+
+  if test $ac_use_included_regex = yes; then
+    AC_DEFINE([_REGEX_INCLUDE_LIMITS_H], [1],
+      [Define if you want <regex.h> to include <limits.h>, so that it
+       consistently overrides <limits.h>'s RE_DUP_MAX.])
+    AC_DEFINE([_REGEX_LARGE_OFFSETS], [1],
+      [Define if you want regoff_t to be at least as wide POSIX requires.])
+    AC_DEFINE([re_syntax_options], [rpl_re_syntax_options],
+      [Define to rpl_re_syntax_options if the replacement should be used.])
+    AC_DEFINE([re_set_syntax], [rpl_re_set_syntax],
+      [Define to rpl_re_set_syntax if the replacement should be used.])
+    AC_DEFINE([re_compile_pattern], [rpl_re_compile_pattern],
+      [Define to rpl_re_compile_pattern if the replacement should be used.])
+    AC_DEFINE([re_compile_fastmap], [rpl_re_compile_fastmap],
+      [Define to rpl_re_compile_fastmap if the replacement should be used.])
+    AC_DEFINE([re_search], [rpl_re_search],
+      [Define to rpl_re_search if the replacement should be used.])
+    AC_DEFINE([re_search_2], [rpl_re_search_2],
+      [Define to rpl_re_search_2 if the replacement should be used.])
+    AC_DEFINE([re_match], [rpl_re_match],
+      [Define to rpl_re_match if the replacement should be used.])
+    AC_DEFINE([re_match_2], [rpl_re_match_2],
+      [Define to rpl_re_match_2 if the replacement should be used.])
+    AC_DEFINE([re_set_registers], [rpl_re_set_registers],
+      [Define to rpl_re_set_registers if the replacement should be used.])
+    AC_DEFINE([re_comp], [rpl_re_comp],
+      [Define to rpl_re_comp if the replacement should be used.])
+    AC_DEFINE([re_exec], [rpl_re_exec],
+      [Define to rpl_re_exec if the replacement should be used.])
+    AC_DEFINE([regcomp], [rpl_regcomp],
+      [Define to rpl_regcomp if the replacement should be used.])
+    AC_DEFINE([regexec], [rpl_regexec],
+      [Define to rpl_regexec if the replacement should be used.])
+    AC_DEFINE([regerror], [rpl_regerror],
+      [Define to rpl_regerror if the replacement should be used.])
+    AC_DEFINE([regfree], [rpl_regfree],
+      [Define to rpl_regfree if the replacement should be used.])
+  fi
+])
+
+# Prerequisites of lib/regex.c and lib/regex_internal.c.
+AC_DEFUN([gl_PREREQ_REGEX],
+[
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+  AC_REQUIRE([AC_C_INLINE])
+  AC_REQUIRE([AC_C_RESTRICT])
+  AC_REQUIRE([AC_TYPE_MBSTATE_T])
+  AC_REQUIRE([gl_EEMALLOC])
+  AC_REQUIRE([gl_GLIBC21])
+  AC_CHECK_HEADERS([libintl.h])
+  AC_CHECK_FUNCS_ONCE([isblank iswctype])
+  AC_CHECK_DECLS([isblank], [], [], [[#include <ctype.h>]])
+])
diff --git a/m4/wchar_h.m4 b/m4/wchar_h.m4
new file mode 100644
index 0000000000..a062ca981d
--- /dev/null
+++ b/m4/wchar_h.m4
@@ -0,0 +1,240 @@
+dnl A placeholder for ISO C99 <wchar.h>, for platforms that have issues.
+
+dnl Copyright (C) 2007-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Eric Blake.
+
+# wchar_h.m4 serial 43
+
+AC_DEFUN([gl_WCHAR_H],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+  AC_REQUIRE([gl_WCHAR_H_INLINE_OK])
+  dnl Prepare for creating substitute <wchar.h>.
+  dnl Check for <wchar.h> (missing in Linux uClibc when built without wide
+  dnl character support).
+  dnl <wchar.h> is always overridden, because of GNULIB_POSIXCHECK.
+  gl_CHECK_NEXT_HEADERS([wchar.h])
+  if test $ac_cv_header_wchar_h = yes; then
+    HAVE_WCHAR_H=1
+  else
+    HAVE_WCHAR_H=0
+  fi
+  AC_SUBST([HAVE_WCHAR_H])
+
+  AC_REQUIRE([gl_FEATURES_H])
+
+  AC_REQUIRE([gt_TYPE_WINT_T])
+  if test $gt_cv_c_wint_t = yes; then
+    HAVE_WINT_T=1
+  else
+    HAVE_WINT_T=0
+  fi
+  AC_SUBST([HAVE_WINT_T])
+
+  AC_REQUIRE([gl_TYPE_WINT_T_PREREQ])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#if !(defined __GLIBC__ && !defined __UCLIBC__)
+# include <stddef.h>
+# include <stdio.h>
+# include <time.h>
+#endif
+#include <wchar.h>
+    ]],
+    [btowc wctob mbsinit mbrtowc mbrlen mbsrtowcs mbsnrtowcs wcrtomb
+     wcsrtombs wcsnrtombs wcwidth wmemchr wmemcmp wmemcpy wmemmove wmemset
+     wcslen wcsnlen wcscpy wcpcpy wcsncpy wcpncpy wcscat wcsncat wcscmp
+     wcsncmp wcscasecmp wcsncasecmp wcscoll wcsxfrm wcsdup wcschr wcsrchr
+     wcscspn wcsspn wcspbrk wcsstr wcstok wcswidth wcsftime
+    ])
+])
+
+dnl Check whether <wchar.h> is usable at all.
+AC_DEFUN([gl_WCHAR_H_INLINE_OK],
+[
+  dnl Test whether <wchar.h> suffers due to the transition from '__inline' to
+  dnl 'gnu_inline'. See <https://sourceware.org/bugzilla/show_bug.cgi?id=4022>
+  dnl and <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42440>. In summary,
+  dnl glibc version 2.5 or older, together with gcc version 4.3 or newer and
+  dnl the option -std=c99 or -std=gnu99, leads to a broken <wchar.h>.
+  AC_CACHE_CHECK([whether <wchar.h> uses 'inline' correctly],
+    [gl_cv_header_wchar_h_correct_inline],
+    [gl_cv_header_wchar_h_correct_inline=yes
+     AC_LANG_CONFTEST([
+       AC_LANG_SOURCE([[#define wcstod renamed_wcstod
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+extern int zero (void);
+int main () { return zero(); }
+]])])
+     dnl Do not rename the object file from conftest.$ac_objext to
+     dnl conftest1.$ac_objext, as this will cause the link to fail on
+     dnl z/OS when using the XPLINK object format (due to duplicate
+     dnl CSECT names). Instead, temporarily redefine $ac_compile so
+     dnl that the object file has the latter name from the start.
+     save_ac_compile="$ac_compile"
+     ac_compile=`echo "$save_ac_compile" | sed s/conftest/conftest1/`
+     if echo '#include "conftest.c"' >conftest1.c &&
+        AC_TRY_EVAL([ac_compile]); then
+       AC_LANG_CONFTEST([
+         AC_LANG_SOURCE([[#define wcstod renamed_wcstod
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+int zero (void) { return 0; }
+]])])
+       dnl See note above about renaming object files.
+       ac_compile=`echo "$save_ac_compile" | sed s/conftest/conftest2/`
+       if echo '#include "conftest.c"' >conftest2.c &&
+          AC_TRY_EVAL([ac_compile]); then
+         if $CC -o conftest$ac_exeext $CFLAGS $LDFLAGS conftest1.$ac_objext conftest2.$ac_objext $LIBS >&AS_MESSAGE_LOG_FD 2>&1; then
+           :
+         else
+           gl_cv_header_wchar_h_correct_inline=no
+         fi
+       fi
+     fi
+     ac_compile="$save_ac_compile"
+     rm -f conftest[12].c conftest[12].$ac_objext conftest$ac_exeext
+    ])
+  if test $gl_cv_header_wchar_h_correct_inline = no; then
+    AC_MSG_ERROR([<wchar.h> cannot be used with this compiler ($CC $CFLAGS $CPPFLAGS).
+This is a known interoperability problem of glibc <= 2.5 with gcc >= 4.3 in
+C99 mode. You have four options:
+  - Add the flag -fgnu89-inline to CC and reconfigure, or
+  - Fix your include files, using parts of
+    <https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=b037a293a48718af30d706c2e18c929d0e69a621>, or
+  - Use a gcc version older than 4.3, or
+  - Don't use the flags -std=c99 or -std=gnu99.
+Configuration aborted.])
+  fi
+])
+
+AC_DEFUN([gl_WCHAR_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_WCHAR_H_DEFAULTS],
+[
+  GNULIB_BTOWC=0;       AC_SUBST([GNULIB_BTOWC])
+  GNULIB_WCTOB=0;       AC_SUBST([GNULIB_WCTOB])
+  GNULIB_MBSINIT=0;     AC_SUBST([GNULIB_MBSINIT])
+  GNULIB_MBRTOWC=0;     AC_SUBST([GNULIB_MBRTOWC])
+  GNULIB_MBRLEN=0;      AC_SUBST([GNULIB_MBRLEN])
+  GNULIB_MBSRTOWCS=0;   AC_SUBST([GNULIB_MBSRTOWCS])
+  GNULIB_MBSNRTOWCS=0;  AC_SUBST([GNULIB_MBSNRTOWCS])
+  GNULIB_WCRTOMB=0;     AC_SUBST([GNULIB_WCRTOMB])
+  GNULIB_WCSRTOMBS=0;   AC_SUBST([GNULIB_WCSRTOMBS])
+  GNULIB_WCSNRTOMBS=0;  AC_SUBST([GNULIB_WCSNRTOMBS])
+  GNULIB_WCWIDTH=0;     AC_SUBST([GNULIB_WCWIDTH])
+  GNULIB_WMEMCHR=0;     AC_SUBST([GNULIB_WMEMCHR])
+  GNULIB_WMEMCMP=0;     AC_SUBST([GNULIB_WMEMCMP])
+  GNULIB_WMEMCPY=0;     AC_SUBST([GNULIB_WMEMCPY])
+  GNULIB_WMEMMOVE=0;    AC_SUBST([GNULIB_WMEMMOVE])
+  GNULIB_WMEMSET=0;     AC_SUBST([GNULIB_WMEMSET])
+  GNULIB_WCSLEN=0;      AC_SUBST([GNULIB_WCSLEN])
+  GNULIB_WCSNLEN=0;     AC_SUBST([GNULIB_WCSNLEN])
+  GNULIB_WCSCPY=0;      AC_SUBST([GNULIB_WCSCPY])
+  GNULIB_WCPCPY=0;      AC_SUBST([GNULIB_WCPCPY])
+  GNULIB_WCSNCPY=0;     AC_SUBST([GNULIB_WCSNCPY])
+  GNULIB_WCPNCPY=0;     AC_SUBST([GNULIB_WCPNCPY])
+  GNULIB_WCSCAT=0;      AC_SUBST([GNULIB_WCSCAT])
+  GNULIB_WCSNCAT=0;     AC_SUBST([GNULIB_WCSNCAT])
+  GNULIB_WCSCMP=0;      AC_SUBST([GNULIB_WCSCMP])
+  GNULIB_WCSNCMP=0;     AC_SUBST([GNULIB_WCSNCMP])
+  GNULIB_WCSCASECMP=0;  AC_SUBST([GNULIB_WCSCASECMP])
+  GNULIB_WCSNCASECMP=0; AC_SUBST([GNULIB_WCSNCASECMP])
+  GNULIB_WCSCOLL=0;     AC_SUBST([GNULIB_WCSCOLL])
+  GNULIB_WCSXFRM=0;     AC_SUBST([GNULIB_WCSXFRM])
+  GNULIB_WCSDUP=0;      AC_SUBST([GNULIB_WCSDUP])
+  GNULIB_WCSCHR=0;      AC_SUBST([GNULIB_WCSCHR])
+  GNULIB_WCSRCHR=0;     AC_SUBST([GNULIB_WCSRCHR])
+  GNULIB_WCSCSPN=0;     AC_SUBST([GNULIB_WCSCSPN])
+  GNULIB_WCSSPN=0;      AC_SUBST([GNULIB_WCSSPN])
+  GNULIB_WCSPBRK=0;     AC_SUBST([GNULIB_WCSPBRK])
+  GNULIB_WCSSTR=0;      AC_SUBST([GNULIB_WCSSTR])
+  GNULIB_WCSTOK=0;      AC_SUBST([GNULIB_WCSTOK])
+  GNULIB_WCSWIDTH=0;    AC_SUBST([GNULIB_WCSWIDTH])
+  GNULIB_WCSFTIME=0;    AC_SUBST([GNULIB_WCSFTIME])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_BTOWC=1;         AC_SUBST([HAVE_BTOWC])
+  HAVE_MBSINIT=1;       AC_SUBST([HAVE_MBSINIT])
+  HAVE_MBRTOWC=1;       AC_SUBST([HAVE_MBRTOWC])
+  HAVE_MBRLEN=1;        AC_SUBST([HAVE_MBRLEN])
+  HAVE_MBSRTOWCS=1;     AC_SUBST([HAVE_MBSRTOWCS])
+  HAVE_MBSNRTOWCS=1;    AC_SUBST([HAVE_MBSNRTOWCS])
+  HAVE_WCRTOMB=1;       AC_SUBST([HAVE_WCRTOMB])
+  HAVE_WCSRTOMBS=1;     AC_SUBST([HAVE_WCSRTOMBS])
+  HAVE_WCSNRTOMBS=1;    AC_SUBST([HAVE_WCSNRTOMBS])
+  HAVE_WMEMCHR=1;       AC_SUBST([HAVE_WMEMCHR])
+  HAVE_WMEMCMP=1;       AC_SUBST([HAVE_WMEMCMP])
+  HAVE_WMEMCPY=1;       AC_SUBST([HAVE_WMEMCPY])
+  HAVE_WMEMMOVE=1;      AC_SUBST([HAVE_WMEMMOVE])
+  HAVE_WMEMSET=1;       AC_SUBST([HAVE_WMEMSET])
+  HAVE_WCSLEN=1;        AC_SUBST([HAVE_WCSLEN])
+  HAVE_WCSNLEN=1;       AC_SUBST([HAVE_WCSNLEN])
+  HAVE_WCSCPY=1;        AC_SUBST([HAVE_WCSCPY])
+  HAVE_WCPCPY=1;        AC_SUBST([HAVE_WCPCPY])
+  HAVE_WCSNCPY=1;       AC_SUBST([HAVE_WCSNCPY])
+  HAVE_WCPNCPY=1;       AC_SUBST([HAVE_WCPNCPY])
+  HAVE_WCSCAT=1;        AC_SUBST([HAVE_WCSCAT])
+  HAVE_WCSNCAT=1;       AC_SUBST([HAVE_WCSNCAT])
+  HAVE_WCSCMP=1;        AC_SUBST([HAVE_WCSCMP])
+  HAVE_WCSNCMP=1;       AC_SUBST([HAVE_WCSNCMP])
+  HAVE_WCSCASECMP=1;    AC_SUBST([HAVE_WCSCASECMP])
+  HAVE_WCSNCASECMP=1;   AC_SUBST([HAVE_WCSNCASECMP])
+  HAVE_WCSCOLL=1;       AC_SUBST([HAVE_WCSCOLL])
+  HAVE_WCSXFRM=1;       AC_SUBST([HAVE_WCSXFRM])
+  HAVE_WCSDUP=1;        AC_SUBST([HAVE_WCSDUP])
+  HAVE_WCSCHR=1;        AC_SUBST([HAVE_WCSCHR])
+  HAVE_WCSRCHR=1;       AC_SUBST([HAVE_WCSRCHR])
+  HAVE_WCSCSPN=1;       AC_SUBST([HAVE_WCSCSPN])
+  HAVE_WCSSPN=1;        AC_SUBST([HAVE_WCSSPN])
+  HAVE_WCSPBRK=1;       AC_SUBST([HAVE_WCSPBRK])
+  HAVE_WCSSTR=1;        AC_SUBST([HAVE_WCSSTR])
+  HAVE_WCSTOK=1;        AC_SUBST([HAVE_WCSTOK])
+  HAVE_WCSWIDTH=1;      AC_SUBST([HAVE_WCSWIDTH])
+  HAVE_WCSFTIME=1;      AC_SUBST([HAVE_WCSFTIME])
+  HAVE_DECL_WCTOB=1;    AC_SUBST([HAVE_DECL_WCTOB])
+  HAVE_DECL_WCWIDTH=1;  AC_SUBST([HAVE_DECL_WCWIDTH])
+  REPLACE_MBSTATE_T=0;  AC_SUBST([REPLACE_MBSTATE_T])
+  REPLACE_BTOWC=0;      AC_SUBST([REPLACE_BTOWC])
+  REPLACE_WCTOB=0;      AC_SUBST([REPLACE_WCTOB])
+  REPLACE_MBSINIT=0;    AC_SUBST([REPLACE_MBSINIT])
+  REPLACE_MBRTOWC=0;    AC_SUBST([REPLACE_MBRTOWC])
+  REPLACE_MBRLEN=0;     AC_SUBST([REPLACE_MBRLEN])
+  REPLACE_MBSRTOWCS=0;  AC_SUBST([REPLACE_MBSRTOWCS])
+  REPLACE_MBSNRTOWCS=0; AC_SUBST([REPLACE_MBSNRTOWCS])
+  REPLACE_WCRTOMB=0;    AC_SUBST([REPLACE_WCRTOMB])
+  REPLACE_WCSRTOMBS=0;  AC_SUBST([REPLACE_WCSRTOMBS])
+  REPLACE_WCSNRTOMBS=0; AC_SUBST([REPLACE_WCSNRTOMBS])
+  REPLACE_WCWIDTH=0;    AC_SUBST([REPLACE_WCWIDTH])
+  REPLACE_WCSWIDTH=0;   AC_SUBST([REPLACE_WCSWIDTH])
+  REPLACE_WCSFTIME=0;   AC_SUBST([REPLACE_WCSFTIME])
+])
diff --git a/m4/wcrtomb.m4 b/m4/wcrtomb.m4
new file mode 100644
index 0000000000..c4e4463097
--- /dev/null
+++ b/m4/wcrtomb.m4
@@ -0,0 +1,114 @@
+# wcrtomb.m4 serial 12
+dnl Copyright (C) 2008-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_WCRTOMB],
+[
+  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
+
+  AC_REQUIRE([AC_TYPE_MBSTATE_T])
+  gl_MBSTATE_T_BROKEN
+
+  AC_CHECK_FUNCS_ONCE([wcrtomb])
+  if test $ac_cv_func_wcrtomb = no; then
+    HAVE_WCRTOMB=0
+    AC_CHECK_DECLS([wcrtomb],,, [[
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+]])
+    if test $ac_cv_have_decl_wcrtomb = yes; then
+      dnl On Minix 3.1.8, the system's <wchar.h> declares wcrtomb() although
+      dnl it does not have the function. Avoid a collision with gnulib's
+      dnl replacement.
+      REPLACE_WCRTOMB=1
+    fi
+  else
+    if test $REPLACE_MBSTATE_T = 1; then
+      REPLACE_WCRTOMB=1
+    else
+      dnl On AIX 4.3, OSF/1 5.1 and Solaris 10, wcrtomb (NULL, 0, NULL) sometimes
+      dnl returns 0 instead of 1.
+      AC_REQUIRE([AC_PROG_CC])
+      AC_REQUIRE([gt_LOCALE_FR])
+      AC_REQUIRE([gt_LOCALE_FR_UTF8])
+      AC_REQUIRE([gt_LOCALE_JA])
+      AC_REQUIRE([gt_LOCALE_ZH_CN])
+      AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+      AC_CACHE_CHECK([whether wcrtomb return value is correct],
+        [gl_cv_func_wcrtomb_retval],
+        [
+          dnl Initial guess, used when cross-compiling or when no suitable locale
+          dnl is present.
+changequote(,)dnl
+          case "$host_os" in
+                                     # Guess no on AIX 4, OSF/1 and Solaris.
+            aix4* | osf* | solaris*) gl_cv_func_wcrtomb_retval="guessing no" ;;
+                                     # Guess yes on native Windows.
+            mingw*)                  gl_cv_func_wcrtomb_retval="guessing yes" ;;
+                                     # Guess yes otherwise.
+            *)                       gl_cv_func_wcrtomb_retval="guessing yes" ;;
+          esac
+changequote([,])dnl
+          if test $LOCALE_FR != none || test $LOCALE_FR_UTF8 != none || test $LOCALE_JA != none || test $LOCALE_ZH_CN != none; then
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#include <locale.h>
+#include <string.h>
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+int main ()
+{
+  int result = 0;
+  if (setlocale (LC_ALL, "$LOCALE_FR") != NULL)
+    {
+      if (wcrtomb (NULL, 0, NULL) != 1)
+        result |= 1;
+    }
+  if (setlocale (LC_ALL, "$LOCALE_FR_UTF8") != NULL)
+    {
+      if (wcrtomb (NULL, 0, NULL) != 1)
+        result |= 2;
+    }
+  if (setlocale (LC_ALL, "$LOCALE_JA") != NULL)
+    {
+      if (wcrtomb (NULL, 0, NULL) != 1)
+        result |= 4;
+    }
+  if (setlocale (LC_ALL, "$LOCALE_ZH_CN") != NULL)
+    {
+      if (wcrtomb (NULL, 0, NULL) != 1)
+        result |= 8;
+    }
+  return result;
+}]])],
+              [gl_cv_func_wcrtomb_retval=yes],
+              [gl_cv_func_wcrtomb_retval=no],
+              [:])
+          fi
+        ])
+      case "$gl_cv_func_wcrtomb_retval" in
+        *yes) ;;
+        *) REPLACE_WCRTOMB=1 ;;
+      esac
+    fi
+  fi
+])
+
+# Prerequisites of lib/wcrtomb.c.
+AC_DEFUN([gl_PREREQ_WCRTOMB], [
+  :
+])
diff --git a/m4/wctype_h.m4 b/m4/wctype_h.m4
new file mode 100644
index 0000000000..15d1ef3253
--- /dev/null
+++ b/m4/wctype_h.m4
@@ -0,0 +1,212 @@
+# wctype_h.m4 serial 21
+
+dnl A placeholder for ISO C99 <wctype.h>, for platforms that lack it.
+
+dnl Copyright (C) 2006-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Paul Eggert.
+
+AC_DEFUN([gl_WCTYPE_H],
+[
+  AC_REQUIRE([gl_WCTYPE_H_DEFAULTS])
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_CHECK_FUNCS_ONCE([iswcntrl])
+  if test $ac_cv_func_iswcntrl = yes; then
+    HAVE_ISWCNTRL=1
+  else
+    HAVE_ISWCNTRL=0
+  fi
+  AC_SUBST([HAVE_ISWCNTRL])
+
+  AC_REQUIRE([gt_TYPE_WINT_T])
+  if test $gt_cv_c_wint_t = yes; then
+    HAVE_WINT_T=1
+  else
+    HAVE_WINT_T=0
+  fi
+  AC_SUBST([HAVE_WINT_T])
+
+  AC_REQUIRE([gl_TYPE_WINT_T_PREREQ])
+
+  gl_CHECK_NEXT_HEADERS([wctype.h])
+  if test $ac_cv_header_wctype_h = yes; then
+    if test $ac_cv_func_iswcntrl = yes; then
+      dnl Linux libc5 has an iswprint function that returns 0 for all arguments.
+      dnl The other functions are likely broken in the same way.
+      AC_CACHE_CHECK([whether iswcntrl works], [gl_cv_func_iswcntrl_works],
+        [
+          AC_RUN_IFELSE(
+            [AC_LANG_SOURCE([[
+               /* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
+                  included before <wchar.h>.
+                  BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
+                  must be included before <wchar.h>.  */
+               #include <stddef.h>
+               #include <stdio.h>
+               #include <time.h>
+               #include <wchar.h>
+               #include <wctype.h>
+               int main () { return iswprint ('x') == 0; }
+            ]])],
+            [gl_cv_func_iswcntrl_works=yes], [gl_cv_func_iswcntrl_works=no],
+            [dnl Guess no on Linux libc5, yes otherwise.
+             AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <stdlib.h>
+                          #if __GNU_LIBRARY__ == 1
+                          Linux libc5 i18n is broken.
+                          #endif]], [])],
+              [gl_cv_func_iswcntrl_works="guessing yes"],
+              [gl_cv_func_iswcntrl_works="guessing no"])
+            ])
+        ])
+    fi
+    HAVE_WCTYPE_H=1
+  else
+    HAVE_WCTYPE_H=0
+  fi
+  AC_SUBST([HAVE_WCTYPE_H])
+
+  case "$gl_cv_func_iswcntrl_works" in
+    *yes) REPLACE_ISWCNTRL=0 ;;
+    *)    REPLACE_ISWCNTRL=1 ;;
+  esac
+  AC_SUBST([REPLACE_ISWCNTRL])
+
+  if test $HAVE_ISWCNTRL = 0 || test $REPLACE_ISWCNTRL = 1; then
+    dnl Redefine all of iswcntrl, ..., iswxdigit in <wctype.h>.
+    :
+  fi
+
+  if test $REPLACE_ISWCNTRL = 1; then
+    REPLACE_TOWLOWER=1
+  else
+    AC_CHECK_FUNCS([towlower])
+    if test $ac_cv_func_towlower = yes; then
+      REPLACE_TOWLOWER=0
+    else
+      AC_CHECK_DECLS([towlower],,,
+        [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
+             included before <wchar.h>.
+             BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
+             must be included before <wchar.h>.  */
+          #include <stddef.h>
+          #include <stdio.h>
+          #include <time.h>
+          #include <wchar.h>
+          #if HAVE_WCTYPE_H
+          # include <wctype.h>
+          #endif
+        ]])
+      if test $ac_cv_have_decl_towlower = yes; then
+        dnl On Minix 3.1.8, the system's <wctype.h> declares towlower() and
+        dnl towupper() although it does not have the functions. Avoid a
+        dnl collision with gnulib's replacement.
+        REPLACE_TOWLOWER=1
+      else
+        REPLACE_TOWLOWER=0
+      fi
+    fi
+  fi
+  AC_SUBST([REPLACE_TOWLOWER])
+
+  if test $HAVE_ISWCNTRL = 0 || test $REPLACE_TOWLOWER = 1; then
+    dnl Redefine towlower, towupper in <wctype.h>.
+    :
+  fi
+
+  dnl We assume that the wctype() and iswctype() functions exist if and only
+  dnl if the type wctype_t is defined in <wchar.h> or in <wctype.h> if that
+  dnl exists.
+  dnl HP-UX 11.00 declares all these in <wchar.h> and lacks <wctype.h>.
+  AC_CACHE_CHECK([for wctype_t], [gl_cv_type_wctype_t],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
+               included before <wchar.h>.
+               BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
+               must be included before <wchar.h>.  */
+            #include <stddef.h>
+            #include <stdio.h>
+            #include <time.h>
+            #include <wchar.h>
+            #if HAVE_WCTYPE_H
+            # include <wctype.h>
+            #endif
+            wctype_t a;
+          ]],
+          [[]])],
+       [gl_cv_type_wctype_t=yes],
+       [gl_cv_type_wctype_t=no])
+    ])
+  if test $gl_cv_type_wctype_t = no; then
+    HAVE_WCTYPE_T=0
+  fi
+
+  dnl We assume that the wctrans() and towctrans() functions exist if and only
+  dnl if the type wctrans_t is defined in <wctype.h>.
+  AC_CACHE_CHECK([for wctrans_t], [gl_cv_type_wctrans_t],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be
+               included before <wchar.h>.
+               BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h>
+               must be included before <wchar.h>.  */
+            #include <stddef.h>
+            #include <stdio.h>
+            #include <time.h>
+            #include <wchar.h>
+            #include <wctype.h>
+            wctrans_t a;
+          ]],
+          [[]])],
+       [gl_cv_type_wctrans_t=yes],
+       [gl_cv_type_wctrans_t=no])
+    ])
+  if test $gl_cv_type_wctrans_t = no; then
+    HAVE_WCTRANS_T=0
+  fi
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#if !(defined __GLIBC__ && !defined __UCLIBC__)
+# include <stddef.h>
+# include <stdio.h>
+# include <time.h>
+# include <wchar.h>
+#endif
+#include <wctype.h>
+    ]],
+    [wctype iswctype wctrans towctrans
+    ])
+])
+
+AC_DEFUN([gl_WCTYPE_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_WCTYPE_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_WCTYPE_H_DEFAULTS],
+[
+  GNULIB_ISWBLANK=0;    AC_SUBST([GNULIB_ISWBLANK])
+  GNULIB_WCTYPE=0;      AC_SUBST([GNULIB_WCTYPE])
+  GNULIB_ISWCTYPE=0;    AC_SUBST([GNULIB_ISWCTYPE])
+  GNULIB_WCTRANS=0;     AC_SUBST([GNULIB_WCTRANS])
+  GNULIB_TOWCTRANS=0;   AC_SUBST([GNULIB_TOWCTRANS])
+  dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_ISWBLANK=1;      AC_SUBST([HAVE_ISWBLANK])
+  HAVE_WCTYPE_T=1;      AC_SUBST([HAVE_WCTYPE_T])
+  HAVE_WCTRANS_T=1;     AC_SUBST([HAVE_WCTRANS_T])
+  REPLACE_ISWBLANK=0;   AC_SUBST([REPLACE_ISWBLANK])
+])
diff --git a/m4/wint_t.m4 b/m4/wint_t.m4
new file mode 100644
index 0000000000..95f6854842
--- /dev/null
+++ b/m4/wint_t.m4
@@ -0,0 +1,74 @@
+# wint_t.m4 serial 7
+dnl Copyright (C) 2003, 2007-2018 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+dnl Test whether <wchar.h> has the 'wint_t' type and whether gnulib's
+dnl <wchar.h> or <wctype.h> would, if present, override 'wint_t'.
+dnl Prerequisite: AC_PROG_CC
+
+AC_DEFUN([gt_TYPE_WINT_T],
+[
+  AC_CACHE_CHECK([for wint_t], [gt_cv_c_wint_t],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
+   before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+            wint_t foo = (wchar_t)'\0';]],
+          [[]])],
+       [gt_cv_c_wint_t=yes],
+       [gt_cv_c_wint_t=no])])
+  if test $gt_cv_c_wint_t = yes; then
+    AC_DEFINE([HAVE_WINT_T], [1], [Define if you have the 'wint_t' type.])
+
+    dnl Determine whether gnulib's <wchar.h> or <wctype.h> would, if present,
+    dnl override 'wint_t'.
+    AC_CACHE_CHECK([whether wint_t is too small],
+      [gl_cv_type_wint_t_too_small],
+      [AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM([[
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be
+   included before <wchar.h>.  */
+#if !(defined __GLIBC__ && !defined __UCLIBC__)
+# include <stddef.h>
+# include <stdio.h>
+# include <time.h>
+#endif
+#include <wchar.h>
+              int verify[sizeof (wint_t) < sizeof (int) ? -1 : 1];
+              ]])],
+           [gl_cv_type_wint_t_too_small=no],
+           [gl_cv_type_wint_t_too_small=yes])])
+    if test $gl_cv_type_wint_t_too_small = yes; then
+      GNULIB_OVERRIDES_WINT_T=1
+    else
+      GNULIB_OVERRIDES_WINT_T=0
+    fi
+  else
+    GNULIB_OVERRIDES_WINT_T=0
+  fi
+  AC_SUBST([GNULIB_OVERRIDES_WINT_T])
+])
+
+dnl Prerequisites of the 'wint_t' override.
+AC_DEFUN([gl_TYPE_WINT_T_PREREQ],
+[
+  AC_CHECK_HEADERS_ONCE([crtdefs.h])
+  if test $ac_cv_header_crtdefs_h = yes; then
+    HAVE_CRTDEFS_H=1
+  else
+    HAVE_CRTDEFS_H=0
+  fi
+  AC_SUBST([HAVE_CRTDEFS_H])
+])
diff --git a/src/Makefile.in b/src/Makefile.in
index c3bcc50349..1aae27b2f9 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -391,7 +391,7 @@ base_obj =
 	emacs.o keyboard.o macros.o keymap.o sysdep.o \
 	buffer.o filelock.o insdel.o marker.o \
 	minibuf.o fileio.o dired.o \
-	cmds.o casetab.o casefiddle.o indent.o search.o regex.o undo.o \
+	cmds.o casetab.o casefiddle.o indent.o search.o regex-emacs.o undo.o \
 	alloc.o data.o doc.o editfns.o callint.o \
 	eval.o floatfns.o fns.o font.o print.o lread.o $(MODULES_OBJ) \
 	syntax.o $(UNEXEC_OBJ) bytecode.o \
diff --git a/src/casetab.c b/src/casetab.c
index 8f806a0647..289dc65b85 100644
--- a/src/casetab.c
+++ b/src/casetab.c
@@ -144,7 +144,7 @@ set_case_table (Lisp_Object table, bool standard)
       set_char_table_extras (table, 2, eqv);
     }
 
-  /* This is so set_image_of_range_1 in regex.c can find the EQV table.  */
+  /* This lets set_image_of_range_1 in regex-emacs.c find the EQV table.  */
   set_char_table_extras (canon, 2, eqv);
 
   if (standard)
diff --git a/src/conf_post.h b/src/conf_post.h
index 080d7b7e68..9758298437 100644
--- a/src/conf_post.h
+++ b/src/conf_post.h
@@ -202,13 +202,6 @@ extern void _DebPrint (const char *fmt, ...);
 #endif
 #endif
 
-#ifdef emacs /* Don't do this for lib-src.  */
-/* Tell regex.c to use a type compatible with Emacs.  */
-#define RE_TRANSLATE_TYPE Lisp_Object
-#define RE_TRANSLATE(TBL, C) char_table_translate (TBL, C)
-#define RE_TRANSLATE_P(TBL) (!EQ (TBL, make_number (0)))
-#endif
-
 /* Tell time_rz.c to use Emacs's getter and setter for TZ.
    Only Emacs uses time_rz so this is OK.  */
 #define getenv_TZ emacs_getenv_TZ
diff --git a/src/deps.mk b/src/deps.mk
index 7b6ae9cd8e..a12321d544 100644
--- a/src/deps.mk
+++ b/src/deps.mk
@@ -71,7 +71,7 @@ cmds.o:
 pre-crt0.o: pre-crt0.c
 dbusbind.o: dbusbind.c termhooks.h frame.h keyboard.h lisp.h $(config_h)
 dired.o: dired.c commands.h buffer.h lisp.h $(config_h) character.h charset.h \
-   coding.h regex.h systime.h blockinput.h atimer.h composite.h \
+   coding.h regex-emacs.h systime.h blockinput.h atimer.h composite.h \
    ../lib/filemode.h ../lib/unistd.h globals.h
 dispnew.o: dispnew.c systime.h commands.h process.h frame.h coding.h \
    window.h buffer.h termchar.h termopts.h termhooks.h cm.h \
@@ -169,20 +169,20 @@ process.o:
    blockinput.h atimer.h coding.h msdos.h nsterm.h composite.h \
    keyboard.h lisp.h globals.h $(config_h) character.h xgselect.h sysselect.h \
    ../lib/unistd.h gnutls.h
-regex.o: regex.c syntax.h buffer.h lisp.h globals.h $(config_h) regex.h \
-   category.h character.h
+regex-emacs.o: regex-emacs.c syntax.h buffer.h lisp.h globals.h $(config_h) \
+   regex-emacs.h category.h character.h
 region-cache.o: region-cache.c buffer.h region-cache.h \
    lisp.h globals.h $(config_h)
 scroll.o: scroll.c termchar.h dispextern.h frame.h msdos.h keyboard.h \
    termhooks.h lisp.h globals.h $(config_h) systime.h coding.h composite.h \
    window.h
-search.o: search.c regex.h commands.h buffer.h region-cache.h syntax.h \
+search.o: search.c regex-emacs.h commands.h buffer.h region-cache.h syntax.h \
    blockinput.h atimer.h systime.h category.h character.h charset.h \
    $(INTERVALS_H) lisp.h globals.h $(config_h)
 sound.o: sound.c dispextern.h syssignal.h lisp.h globals.h $(config_h) \
    atimer.h systime.h ../lib/unistd.h msdos.h
 syntax.o: syntax.c syntax.h buffer.h commands.h category.h character.h \
-   keymap.h regex.h $(INTERVALS_H) lisp.h globals.h $(config_h)
+   keymap.h regex-emacs.h $(INTERVALS_H) lisp.h globals.h $(config_h)
 sysdep.o: sysdep.c syssignal.h systty.h systime.h syswait.h blockinput.h \
    process.h dispextern.h termhooks.h termchar.h termopts.h coding.h \
    frame.h atimer.h window.h msdos.h dosfns.h keyboard.h cm.h lisp.h \
diff --git a/src/emacs.c b/src/emacs.c
index 861d70735c..ee77096918 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -84,7 +84,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 #include "composite.h"
 #include "dispextern.h"
 #include "ptr-bounds.h"
-#include "regex.h"
+#include "regex-emacs.h"
 #include "sheap.h"
 #include "syntax.h"
 #include "sysselect.h"
@@ -846,9 +846,9 @@ main (int argc, char **argv)
     {
       rlim_t lim = rlim.rlim_cur;
 
-      /* Approximate the amount regex.c needs per unit of
+      /* Approximate the amount regex-emacs.c needs per unit of
 	 emacs_re_max_failures, then add 33% to cover the size of the
-	 smaller stacks that regex.c successively allocates and
+	 smaller stacks that regex-emacs.c successively allocates and
 	 discards on its way to the maximum.  */
       int min_ratio = 20 * sizeof (char *);
       int ratio = min_ratio + min_ratio / 3;
@@ -887,7 +887,7 @@ main (int argc, char **argv)
 		lim = newlim;
 	    }
 	}
-      /* If the stack is big enough, let regex.c more of it before
+      /* If the stack is big enough, give regex-emacs.c more of it before
          falling back to heap allocation.  */
       emacs_re_safe_alloca = max
         (min (lim - extra, SIZE_MAX) * (min_ratio / ratio),
diff --git a/src/regex.c b/src/regex-emacs.c
similarity index 99%
rename from src/regex.c
rename to src/regex-emacs.c
index 6ee13c4c99..968a25dc79 100644
--- a/src/regex.c
+++ b/src/regex-emacs.c
@@ -53,7 +53,7 @@
 #include <stdlib.h>
 
 #ifdef emacs
-/* We need this for `regex.h', and perhaps for the Emacs include files.  */
+/* We need this for regex-emacs.h, and perhaps for the Emacs include files.  */
 # include <sys/types.h>
 #endif
 
@@ -289,7 +289,7 @@ enum syntaxcode { Swhitespace = 0, Sword = 1, Ssymbol = 2 };
 #endif
 
 /* Get the interface, including the syntax bits.  */
-#include "regex.h"
+#include "regex-emacs.h"
 
 /* isalpha etc. are used for the character classes.  */
 #include <ctype.h>
@@ -1157,7 +1157,7 @@ reg_syntax_t re_syntax_options;
    different, incompatible syntaxes.
 
    The argument SYNTAX is a bit mask comprised of the various bits
-   defined in regex.h.  We return the old syntax.  */
+   defined in regex-emacs.h.  We return the old syntax.  */
 
 reg_syntax_t
 re_set_syntax (reg_syntax_t syntax)
@@ -1172,7 +1172,7 @@ WEAK_ALIAS (__re_set_syntax, re_set_syntax)
 #endif
 
 /* This table gives an error message for each of the error codes listed
-   in regex.h.  Obviously the order here has to be same as there.
+   in regex-emacs.h.  Obviously the order here has to be same as there.
    POSIX doesn't require that we do anything for REG_NOERROR,
    but why not be nice?  */
 
@@ -1474,28 +1474,28 @@ do {									\
   char *destination;							\
   /* Must be int, so when we don't save any registers, the arithmetic	\
      of 0 + -1 isn't done as unsigned.  */				\
-  									\
+									\
   DEBUG_STATEMENT (nfailure_points_pushed++);				\
   DEBUG_PRINT ("\nPUSH_FAILURE_POINT:\n");				\
   DEBUG_PRINT ("  Before push, next avail: %zd\n", (fail_stack).avail);	\
   DEBUG_PRINT ("			size: %zd\n", (fail_stack).size);\
-  									\
+									\
   ENSURE_FAIL_STACK (NUM_NONREG_ITEMS);					\
-  									\
+									\
   DEBUG_PRINT ("\n");							\
-  									\
+									\
   DEBUG_PRINT ("  Push frame index: %zd\n", fail_stack.frame);		\
   PUSH_FAILURE_INT (fail_stack.frame);					\
-  									\
+									\
   DEBUG_PRINT ("  Push string %p: \"", string_place);			\
   DEBUG_PRINT_DOUBLE_STRING (string_place, string1, size1, string2, size2);\
   DEBUG_PRINT ("\"\n");							\
   PUSH_FAILURE_POINTER (string_place);					\
-  									\
+									\
   DEBUG_PRINT ("  Push pattern %p: ", pattern);				\
   DEBUG_PRINT_COMPILED_PATTERN (bufp, pattern, pend);			\
   PUSH_FAILURE_POINTER (pattern);					\
-  									\
+									\
   /* Close the frame by moving the frame pointer past it.  */		\
   fail_stack.frame = fail_stack.avail;					\
 } while (0)
@@ -1822,7 +1822,7 @@ struct range_table_work_area
 #define SETUP_ASCII_RANGE(work_area, FROM, TO)			\
   do {								\
     int C0, C1;							\
-    								\
+								\
     for (C0 = (FROM); C0 <= (TO); C0++)				\
       {								\
 	C1 = TRANSLATE (C0);					\
@@ -1843,7 +1843,7 @@ struct range_table_work_area
   do {									       \
     int C0, C1, C2, I;							       \
     int USED = RANGE_TABLE_WORK_USED (work_area);			       \
-    									       \
+									       \
     for (C0 = (FROM); C0 <= (TO); C0++)					       \
       {									       \
 	C1 = RE_CHAR_TO_MULTIBYTE (C0);					       \
@@ -1882,7 +1882,7 @@ struct range_table_work_area
 #define SETUP_MULTIBYTE_RANGE(work_area, FROM, TO)			   \
   do {									   \
     int C0, C1, C2, I, USED = RANGE_TABLE_WORK_USED (work_area);	   \
-    									   \
+									   \
     SET_RANGE_TABLE_WORK_AREA ((work_area), (FROM), (TO));		   \
     for (C0 = (FROM); C0 <= (TO); C0++)					   \
       {									   \
@@ -1896,7 +1896,7 @@ struct range_table_work_area
 	  {								   \
 	    int from = RANGE_TABLE_WORK_ELT (work_area, I);		   \
 	    int to = RANGE_TABLE_WORK_ELT (work_area, I + 1);		   \
-	    								   \
+									   \
 	    if (C1 >= from - 1 && C1 <= to + 1)				   \
 	      {								   \
 		if (C1 == from - 1)					   \
@@ -2371,7 +2371,7 @@ static boolean group_in_compile_stack (compile_stack_type compile_stack,
 				       regnum_t regnum);
 
 /* `regex_compile' compiles PATTERN (of length SIZE) according to SYNTAX.
-   Returns one of error codes defined in `regex.h', or zero for success.
+   Returns one of error codes defined in regex-emacs.h, or zero for success.
 
    If WHITESPACE_REGEXP is given (only #ifdef emacs), it is used instead of
    a space character in PATTERN.
@@ -2714,15 +2714,15 @@ regex_compile (re_char *pattern, size_t size,
 
 		    if (!zero_times_ok && simple)
 		      { /* Since simple * loops can be made faster by using
-		    	   on_failure_keep_string_jump, we turn simple P+
-		    	   into PP* if P is simple.  */
-		    	unsigned char *p1, *p2;
-		    	startoffset = b - laststart;
-		    	GET_BUFFER_SPACE (startoffset);
-		    	p1 = b; p2 = laststart;
-		    	while (p2 < p1)
-		    	  *b++ = *p2++;
-		    	zero_times_ok = 1;
+			   on_failure_keep_string_jump, we turn simple P+
+			   into PP* if P is simple.  */
+			unsigned char *p1, *p2;
+			startoffset = b - laststart;
+			GET_BUFFER_SPACE (startoffset);
+			p1 = b; p2 = laststart;
+			while (p2 < p1)
+			  *b++ = *p2++;
+			zero_times_ok = 1;
 		      }
 
 		    GET_BUFFER_SPACE (6);
@@ -6217,7 +6217,7 @@ re_match_2_internal (struct re_pattern_buffer *bufp, re_char *string1,
 
   FREE_VARIABLES ();
 
-  return -1;         			/* Failure to match.  */
+  return -1;	/* Failure to match.  */
 }
 
 /* Subroutine definitions for re_match_2.  */
@@ -6400,7 +6400,7 @@ re_exec (const char *s)
      routine will report only success or failure, and nothing about the
      registers.
 
-   It returns 0 if it succeeds, nonzero if it doesn't.  (See regex.h for
+   It returns 0 if it succeeds, nonzero if it doesn't.  (See regex-emacs.h for
    the return codes and their meanings.)  */
 
 reg_errcode_t
diff --git a/src/regex.h b/src/regex-emacs.h
similarity index 98%
rename from src/regex.h
rename to src/regex-emacs.h
index 3a2d74d86a..8a15e5793f 100644
--- a/src/regex.h
+++ b/src/regex-emacs.h
@@ -160,9 +160,9 @@ typedef unsigned long reg_syntax_t;
 
 /* If this bit is set, turn on internal regex debugging.
    If not set, and debugging was on, turn it off.
-   This only works if regex.c is compiled -DDEBUG.
+   This only works if regex-emacs.c is compiled -DDEBUG.
    We define this bit always, so that all that's needed to turn on
-   debugging is to recompile regex.c; the calling code can always have
+   debugging is to recompile regex-emacs.c; the calling code can always have
    this bit set, and it won't affect anything in the normal case. */
 #define RE_DEBUG (RE_NO_NEWLINE_ANCHOR << 1)
 
@@ -219,7 +219,7 @@ extern ptrdiff_t emacs_re_safe_alloca;
   ((RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS | RE_DEBUG)	\
    & ~(RE_DOT_NOT_NULL | RE_INTERVALS | RE_CONTEXT_INDEP_OPS))
 
-#define RE_SYNTAX_POSIX_AWK 						\
+#define RE_SYNTAX_POSIX_AWK						\
   (RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS		\
    | RE_INTERVALS	    | RE_NO_GNU_OPS)
 
@@ -317,7 +317,7 @@ extern ptrdiff_t emacs_re_safe_alloca;

 /* If any error codes are removed, changed, or added, update the
-   `re_error_msg' table in regex.c.  */
+   re_error_msg table in regex-emacs.c.  */
 typedef enum
 {
 #ifdef _XOPEN_SOURCE
@@ -350,6 +350,11 @@ typedef enum
   REG_ESIZEBR           /* n or m too big in \{n,m\} */
 } reg_errcode_t;
 
+/* Use a type compatible with Emacs.  */
+#define RE_TRANSLATE_TYPE Lisp_Object
+#define RE_TRANSLATE(TBL, C) char_table_translate (TBL, C)
+#define RE_TRANSLATE_P(TBL) (!EQ (TBL, make_number (0)))
+
 /* This data structure represents a compiled pattern.  Before calling
    the pattern compiler, the fields `buffer', `allocated', `fastmap',
    `translate', and `no_sub' can be set.  After the pattern has been
@@ -650,5 +655,5 @@ typedef int re_wchar_t;
 
 #endif /* not WIDE_CHAR_SUPPORT */
 
-#endif /* regex.h */
+#endif /* regex-emacs.h */
 
diff --git a/src/search.c b/src/search.c
index ccdb659776..4ee70144fc 100644
--- a/src/search.c
+++ b/src/search.c
@@ -30,7 +30,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 #include "blockinput.h"
 #include "intervals.h"
 
-#include "regex.h"
+#include "regex-emacs.h"
 
 #define REGEXP_CACHE_SIZE 20
 
@@ -290,7 +290,7 @@ looking_at_1 (Lisp_Object string, bool posix)
   if (running_asynch_code)
     save_search_regs ();
 
-  /* This is so set_image_of_range_1 in regex.c can find the EQV table.  */
+  /* This lets set_image_of_range_1 in regex-emacs.c find the EQV table.  */
   set_char_table_extras (BVAR (current_buffer, case_canon_table), 2,
 			 BVAR (current_buffer, case_eqv_table));
 
@@ -410,7 +410,7 @@ string_match_1 (Lisp_Object regexp, Lisp_Object string, Lisp_Object start,
       pos_byte = string_char_to_byte (string, pos);
     }
 
-  /* This is so set_image_of_range_1 in regex.c can find the EQV table.  */
+  /* This lets set_image_of_range_1 in regex-emacs.c find the EQV table.  */
   set_char_table_extras (BVAR (current_buffer, case_canon_table), 2,
 			 BVAR (current_buffer, case_eqv_table));
 
@@ -1062,7 +1062,7 @@ search_command (Lisp_Object string, Lisp_Object bound, Lisp_Object noerror,
 	lim_byte = CHAR_TO_BYTE (lim);
     }
 
-  /* This is so set_image_of_range_1 in regex.c can find the EQV table.  */
+  /* This lets set_image_of_range_1 in regex-emacs.c find the EQV table.  */
   set_char_table_extras (BVAR (current_buffer, case_canon_table), 2,
 			 BVAR (current_buffer, case_eqv_table));
 
diff --git a/src/syntax.c b/src/syntax.c
index c5a4b03955..5b875ad296 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -23,7 +23,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 #include "lisp.h"
 #include "character.h"
 #include "buffer.h"
-#include "regex.h"
+#include "regex-emacs.h"
 #include "syntax.h"
 #include "intervals.h"
 #include "category.h"
@@ -267,7 +267,7 @@ SETUP_SYNTAX_TABLE (ptrdiff_t from, ptrdiff_t count)
    If it is t (which is only used in fast_c_string_match_ignore_case),
    ignore properties altogether.
 
-   This is meant for regex.c to use.  For buffers, regex.c passes arguments
+   This is meant so that for buffers, regex-emacs.c passes arguments
    to the UPDATE_SYNTAX_TABLE functions which are relative to BEGV.
    So if it is a buffer, we set the offset field to BEGV.  */
 
@@ -3729,7 +3729,7 @@ syms_of_syntax (void)
   staticpro (&gl_state.current_syntax_table);
   staticpro (&gl_state.old_prop);
 
-  /* Defined in regex.c.  */
+  /* Defined in regex-emacs.c.  */
   staticpro (&re_match_object);
 
   DEFSYM (Qscan_error, "scan-error");
diff --git a/src/thread.h b/src/thread.h
index c10e5ecb75..dc5d5eca31 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -19,7 +19,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 #ifndef THREAD_H
 #define THREAD_H
 
-#include "regex.h"
+#include "regex-emacs.h"
 
 #ifdef WINDOWSNT
 #include <sys/socket.h>
diff --git a/test/src/regex-tests.el b/test/src/regex-emacs-tests.el
similarity index 99%
rename from test/src/regex-tests.el
rename to test/src/regex-emacs-tests.el
index 083ed5c4c8..7a075908a6 100644
--- a/test/src/regex-tests.el
+++ b/test/src/regex-emacs-tests.el
@@ -1,4 +1,4 @@
-;;; regex-tests.el --- tests for regex.c functions -*- lexical-binding: t -*-
+;;; regex-emacs-tests.el --- tests for regex-emacs.c -*- lexical-binding: t -*-
 
 ;; Copyright (C) 2015-2018 Free Software Foundation, Inc.
 
@@ -24,7 +24,7 @@
 (defvar regex-tests--resources-dir
   (concat (concat (file-name-directory (or load-file-name buffer-file-name))
                   "/regex-resources/"))
-  "Path to regex-resources directory next to the \"regex-tests.el\" file.")
+  "Path to regex-resources directory next to the \"regex-emacs-tests.el\" file.")
 
 (ert-deftest regex-word-cc-fallback-test ()
   "Test that \"[[:cc:]]*x\" matches \"x\" (bug#24020).
@@ -683,4 +683,4 @@ regex-tests-TESTS
   (should-not (string-match "\\`x\\{65535\\}" (make-string 65534 ?x)))
   (should-error (string-match "\\`x\\{65536\\}" "X") :type 'invalid-regexp))
 
-;;; regex-tests.el ends here
+;;; regex-emacs-tests.el ends here
-- 
2.17.1