Subject: Re: Bash-specific performance by avoiding sed

From: Pavel Raiskup <[email-masked]>
Date: Mon, 12 Oct 2015 19:38:40 +0200

On Friday 09 of October 2015 17:16:03 Pavel Raiskup wrote:
> > Here's a (lightly-tested) idea of what it would look like, where we'd
> > have to audit every caller to deal with the result already including
> > full quoting:
> > 
> > if test yes = `(x=; printf -v x %q yes; echo $x) 2>/dev/null`; then
> >   func_quote()
> >   {
> >     printf -v func_quote_result %q "$1"
> >   }
> > else
> >   func_quote()
> >   {
> >     portable version, except add:
> >     func_quote_result="\"$func_quote_result\""
> >   }
> > fi
> >
> > Note that with this variant, the portable version converts 'a  *"b' into
> > '"a  *\"b"', while the bash version converts it into 'a\ \ \*\"b'.
> 
> Thanks!  I've done a simple testing too .. and it seems to be equivalent
> to '$SED $sed_quote_subst' (in usecases like: string -> quote -> eval).
> 
> Well -- I'm not 100% sure I want to hack this in and risk some issues.  On
> the other hand, I'm able to review the patches if somebody wanted to give
> it a try (the small bash slowdown from v2.4.2 to v2.4.6 is not good
> motivation for me).

Hm, I was thinking thinking about this over the weekend and I wanted to do
some testing before I would definitely reject that idea.  But it sounds
like the printf builtin helps lets say significantly to bash and does not
hurt others.  I changed the function names so the changes to libtool code
should be pretty transparent (even though it is rather large change).

I'm posting results of the performance test (on systemd package) and
attaching 3 "planned to be pushed" patches.  So testing '2.4.2' version
(fast), git-version after applying 0001 and 0002 (patch-2) and including
0003 (patch-3).

The dirname of test is in format 'PACKAGE-SHELL-LTVERSION'.

Pavel
-----

%E  %U  %S (/home/praiskup/rh/projects/systemd-perf/systemd-bash-2.4.2)
0:28.50 56.84 41.42
0:28.38 56.72 41.41
0:28.26 56.44 41.68
%E  %U  %S (/home/praiskup/rh/projects/systemd-perf/systemd-bash-2.4.6.13-f729)
1:06.13 232.12  23.33
1:06.52 232.28  23.35
1:06.54 232.16  23.52
%E  %U  %S (/home/praiskup/rh/projects/systemd-perf/systemd-bash-2.4.6.14-7a09)
0:46.52 151.16  24.48
0:46.64 150.80  24.60
0:46.69 151.12  23.85

%E  %U  %S (/home/praiskup/rh/projects/systemd-perf/systemd-dash-2.4.2)
0:16.34 22.22 28.62
0:17.13 22.57 29.09
0:17.11 22.37 29.24
%E  %U  %S (/home/praiskup/rh/projects/systemd-perf/systemd-dash-2.4.6.13-f729)
0:23.38 58.80 21.32
0:23.16 58.81 21.16
0:23.21 58.67 21.15
%E  %U  %S (/home/praiskup/rh/projects/systemd-perf/systemd-dash-2.4.6.14-7a09)
0:21.36 51.20 21.62
0:21.23 50.59 21.76
0:21.25 50.70 21.55

%E  %U  %S (/home/praiskup/rh/projects/systemd-perf/systemd-ksh-2.4.2)
0:19.65 30.76 34.12
0:21.09 30.68 34.63
0:19.75 30.83 34.29
%E  %U  %S (/home/praiskup/rh/projects/systemd-perf/systemd-ksh-2.4.6.13-f729)
0:30.75 85.60 25.41
0:30.70 85.51 25.52
0:30.80 85.65 25.41
%E  %U  %S (/home/praiskup/rh/projects/systemd-perf/systemd-ksh-2.4.6.14-7a09)
0:30.78 84.25 26.14
0:30.63 83.65 26.17
0:30.62 83.85 26.02

%E  %U  %S (/home/praiskup/rh/projects/systemd-perf/systemd-zsh-2.4.2)
0:27.94 44.47 48.97
0:28.03 44.29 49.31
0:28.60 44.48 48.93
%E  %U  %S (/home/praiskup/rh/projects/systemd-perf/systemd-zsh-2.4.6.13-f729)
0:47.60 140.30  41.70
0:47.53 139.84  41.89
0:47.56 139.71  42.12
%E  %U  %S (/home/praiskup/rh/projects/systemd-perf/systemd-zsh-2.4.6.14-7a09)
0:46.21 131.88  41.72
0:46.62 131.31  42.25
0:46.44 131.35  42.03
>From 32f0df9835ac15ac17e04be57c368172c3ad1d19 Mon Sep 17 00:00:00 2001
From: Pavel Raiskup <[email-masked]>
Date: Sun, 4 Oct 2015 21:55:03 +0200
Subject: [PATCH 1/3] libtool: mitigate the $sed_quote_subst slowdown

When it is reasonably possible, use shell implementation for
quoting.

References:
http://lists.gnu.org/archive/html/libtool/2015-03/msg00005.html
http://lists.gnu.org/archive/html/libtool/2015-02/msg00000.html
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=20006

* gl/build-aux/funclib.sh (func_quote): New function that can be
used as substitution for '$SED $sed_quote_subst' call.
* build-aux/ltmain.in (func_emit_wrapper): Use func_quote instead
of '$SED $sed_quote_subst'.
(func_mode_link): Likewise.
* NEWS: Document.
* bootstrap: Sync with funclib.sh.
---
 NEWS                    |  3 +++
 bootstrap               | 61 +++++++++++++++++++++++++++++++++++++++++++------
 build-aux/ltmain.in     | 10 ++++----
 gl/build-aux/funclib.sh | 61 +++++++++++++++++++++++++++++++++++++++++++------
 4 files changed, 117 insertions(+), 18 deletions(-)

diff --git a/NEWS b/NEWS
index a3c5b12..7c23d03 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,9 @@ NEWS - list of user-visible changes between releases of GNU Libtool
   - Fix significant slowdown of libtoolize for certain projects (regression
     introduced in 2.4.3 release) caused by infinite m4 macro recursion.
 
+  - Mitigate the slowdown of libtool script (introduced in v2.4.3) caused by
+    increased number of calls to '$SED $sed_quote_subst' (bug#20006).
+
 * Noteworthy changes in release 2.4.6 (2015-02-15) [stable]
 
 ** New features:
diff --git a/bootstrap b/bootstrap
index c179f51..fe9e9ca 100755
--- a/bootstrap
+++ b/bootstrap
@@ -230,7 +230,7 @@ vc_ignore=
 
 # Source required external libraries:
 # Set a version string for this script.
-scriptversion=2015-01-20.17; # UTC
+scriptversion=2015-10-04.22; # UTC
 
 # General shell script boiler plate, and helper functions.
 # Written by Gary V. Vaughan, 2004
@@ -1257,6 +1257,57 @@ func_relative_path ()
 }

+# func_quote ARG
+# --------------
+# Aesthetically quote one ARG, store the result into $func_quote_result.  Note
+# that we keep attention to performance here (so far O(N) complexity as long as
+# func_append is O(1)).
+func_quote ()
+{
+    $debug_cmd
+
+    func_quote_result=$1
+
+    case $func_quote_result in
+      *[\\\`\"\$]*)
+        case $func_quote_result in
+          *'*'*|*'['*)
+            func_quote_result=`$ECHO "$func_quote_result" | $SED "$sed_quote_subst"`
+            return 0
+            ;;
+        esac
+
+        func_quote_old_IFS=$IFS
+        for _G_char in '\' '`' '"' '$'
+        do
+          # STATE($1) PREV($2) SEPARATOR($3)
+          set start "" ""
+          func_quote_result=dummy"$_G_char$func_quote_result$_G_char"dummy
+          IFS=$_G_char
+          for _G_part in $func_quote_result
+          do
+            case $1 in
+            quote)
+              func_append func_quote_result "$3$2"
+              set quote "$_G_part" "\\$_G_char"
+              ;;
+            start)
+              set first "" ""
+              func_quote_result=
+              ;;
+            first)
+              set quote "$_G_part" ""
+              ;;
+            esac
+          done
+          IFS=$func_quote_old_IFS
+        done
+        ;;
+      *) ;;
+    esac
+}
+
+
 # func_quote_for_eval ARG...
 # --------------------------
 # Aesthetically quote ARGs to be evaled later.
@@ -1273,12 +1324,8 @@ func_quote_for_eval ()
     func_quote_for_eval_unquoted_result=
     func_quote_for_eval_result=
     while test 0 -lt $#; do
-      case $1 in
-        *[\\\`\"\$]*)
-	  _G_unquoted_arg=`printf '%s\n' "$1" |$SED "$sed_quote_subst"` ;;
-        *)
-          _G_unquoted_arg=$1 ;;
-      esac
+      func_quote "$1"
+      _G_unquoted_arg=$func_quote_result
       if test -n "$func_quote_for_eval_unquoted_result"; then
 	func_append func_quote_for_eval_unquoted_result " $_G_unquoted_arg"
       else
diff --git a/build-aux/ltmain.in b/build-aux/ltmain.in
index 0c40da0..24acefd 100644
--- a/build-aux/ltmain.in
+++ b/build-aux/ltmain.in
@@ -3346,7 +3346,8 @@ else
   if test \"\$libtool_execute_magic\" != \"$magic\"; then
     file=\"\$0\""
 
-    qECHO=`$ECHO "$ECHO" | $SED "$sed_quote_subst"`
+    func_quote "$ECHO"
+    qECHO=$func_quote_result
     $ECHO "\
 
 # A function that is used when there is no print builtin or printf.
@@ -8596,8 +8597,8 @@ EOF
 	    relink_command="$var=$func_quote_for_eval_result; export $var; $relink_command"
 	  fi
 	done
-	relink_command="(cd `pwd`; $relink_command)"
-	relink_command=`$ECHO "$relink_command" | $SED "$sed_quote_subst"`
+	func_quote "(cd `pwd`; $relink_command)"
+	relink_command=$func_quote_result
       fi
 
       # Only actually do things if not in dry run mode.
@@ -8843,7 +8844,8 @@ EOF
       done
       # Quote the link command for shipping.
       relink_command="(cd `pwd`; $SHELL \"$progpath\" $preserve_args --mode=relink $libtool_args @inst_prefix_dir@)"
-      relink_command=`$ECHO "$relink_command" | $SED "$sed_quote_subst"`
+      func_quote "$relink_command"
+      relink_command=$func_quote_result
       if test yes = "$hardcode_automatic"; then
 	relink_command=
       fi
diff --git a/gl/build-aux/funclib.sh b/gl/build-aux/funclib.sh
index 39d972e..47d8b95 100644
--- a/gl/build-aux/funclib.sh
+++ b/gl/build-aux/funclib.sh
@@ -1,5 +1,5 @@
 # Set a version string for this script.
-scriptversion=2015-01-20.17; # UTC
+scriptversion=2015-10-04.22; # UTC
 
 # General shell script boiler plate, and helper functions.
 # Written by Gary V. Vaughan, 2004
@@ -1026,6 +1026,57 @@ func_relative_path ()
 }

+# func_quote ARG
+# --------------
+# Aesthetically quote one ARG, store the result into $func_quote_result.  Note
+# that we keep attention to performance here (so far O(N) complexity as long as
+# func_append is O(1)).
+func_quote ()
+{
+    $debug_cmd
+
+    func_quote_result=$1
+
+    case $func_quote_result in
+      *[\\\`\"\$]*)
+        case $func_quote_result in
+          *[\[\*\?]*)
+            func_quote_result=`$ECHO "$func_quote_result" | $SED "$sed_quote_subst"`
+            return 0
+            ;;
+        esac
+
+        func_quote_old_IFS=$IFS
+        for _G_char in '\' '`' '"' '$'
+        do
+          # STATE($1) PREV($2) SEPARATOR($3)
+          set start "" ""
+          func_quote_result=dummy"$_G_char$func_quote_result$_G_char"dummy
+          IFS=$_G_char
+          for _G_part in $func_quote_result
+          do
+            case $1 in
+            quote)
+              func_append func_quote_result "$3$2"
+              set quote "$_G_part" "\\$_G_char"
+              ;;
+            start)
+              set first "" ""
+              func_quote_result=
+              ;;
+            first)
+              set quote "$_G_part" ""
+              ;;
+            esac
+          done
+          IFS=$func_quote_old_IFS
+        done
+        ;;
+      *) ;;
+    esac
+}
+
+
 # func_quote_for_eval ARG...
 # --------------------------
 # Aesthetically quote ARGs to be evaled later.
@@ -1042,12 +1093,8 @@ func_quote_for_eval ()
     func_quote_for_eval_unquoted_result=
     func_quote_for_eval_result=
     while test 0 -lt $#; do
-      case $1 in
-        *[\\\`\"\$]*)
-	  _G_unquoted_arg=`printf '%s\n' "$1" |$SED "$sed_quote_subst"` ;;
-        *)
-          _G_unquoted_arg=$1 ;;
-      esac
+      func_quote "$1"
+      _G_unquoted_arg=$func_quote_result
       if test -n "$func_quote_for_eval_unquoted_result"; then
 	func_append func_quote_for_eval_unquoted_result " $_G_unquoted_arg"
       else
-- 
2.5.0

>From b5cadd557ef345fb90cd4375f3bc1299d704077c Mon Sep 17 00:00:00 2001
From: Pavel Raiskup <[email-masked]>
Date: Mon, 5 Oct 2015 13:16:08 +0200
Subject: [PATCH 2/3] libtool: optimizing options-parser hooks

Its not necessary to (re)func_quote_for_eval in each function in
the hook hierarchy.  Usually is enough if the leaf function
does func_quote_for_eval and its caller just re-uses the
<CALLEE>_return variable.

This is follow up for the previous commit.

* gl/build-aux/options-parser (func_run_hooks): Propagate
$EXIT_SUCCESS return code down to caller if *any* hook succeeded.
Never re-quote the result -- either the arguments are left
untouched, or the options have already been properly quoted by
succeeding hooks.
(func_parse_options): Quote '$@' and return $EXIT_SUCCESS only if
we changed something.
(func_validate_options): Likewise.
(func_options_prep): Likewise.
(func_options_finish): New hook-caller for 'func_options' hooks.
(func_options): Propagate return value down to top-level caller,
but pay attention we have always set $func_options_result.
* build-aux/ltmain.in (libtool_options_prep): Quote '$@' and
return $EXIT_SUCCESS only if we changed something.
(libtool_parse_options): Likewise.
* bootstrap: Sync gl/build-aux/with option-parser.
---
 bootstrap                   | 171 +++++++++++++++++++++++++++++++-------------
 build-aux/ltmain.in         |  35 ++++++---
 gl/build-aux/options-parser | 171 +++++++++++++++++++++++++++++++-------------
 3 files changed, 271 insertions(+), 106 deletions(-)

diff --git a/bootstrap b/bootstrap
index fe9e9ca..4f00096 100755
--- a/bootstrap
+++ b/bootstrap
@@ -1583,7 +1583,7 @@ func_lt_ver ()
 #! /bin/sh
 
 # Set a version string for this script.
-scriptversion=2014-01-07.03; # UTC
+scriptversion=2015-10-07.11; # UTC
 
 # A portable, pluggable option parser for Bourne shell.
 # Written by Gary V. Vaughan, 2010
@@ -1743,6 +1743,8 @@ func_run_hooks ()
 {
     $debug_cmd
 
+    _G_rc_run_hooks=false
+
     case " $hookable_fns " in
       *" $1 "*) ;;
       *) func_fatal_error "'$1' does not support hook funcions.n" ;;
@@ -1751,16 +1753,16 @@ func_run_hooks ()
     eval _G_hook_fns=\$$1_hooks; shift
 
     for _G_hook in $_G_hook_fns; do
-      eval $_G_hook '"$@"'
-
-      # store returned options list back into positional
-      # parameters for next 'cmd' execution.
-      eval _G_hook_result=\$${_G_hook}_result
-      eval set dummy "$_G_hook_result"; shift
+      if eval $_G_hook '"$@"'; then
+        # store returned options list back into positional
+        # parameters for next 'cmd' execution.
+        eval _G_hook_result=\$${_G_hook}_result
+        eval set dummy "$_G_hook_result"; shift
+        _G_rc_run_hooks=:
+      fi
     done
 
-    func_quote_for_eval ${1+"$@"}
-    func_run_hooks_result=$func_quote_for_eval_result
+    $_G_rc_run_hooks && func_run_hooks_result=$_G_hook_result
 }

@@ -1770,10 +1772,16 @@ func_run_hooks ()
 ## --------------- ##
 
 # In order to add your own option parsing hooks, you must accept the
-# full positional parameter list in your hook function, remove any
-# options that you action, and then pass back the remaining unprocessed
+# full positional parameter list in your hook function, you may remove/edit
+# any options that you action, and then pass back the remaining unprocessed
 # options in '<hooked_function_name>_result', escaped suitably for
-# 'eval'.  Like this:
+# 'eval'.  In this case you also must return $EXIT_SUCCESS to let the
+# hook's caller know that it should pay attention to
+# '<hooked_function_name>_result'.  Returning $EXIT_FAILURE signalizes that
+# arguments are left untouched by the hook and therefore caller will ignore the
+# result variable.
+#
+# Like this:
 #
 #    my_options_prep ()
 #    {
@@ -1783,9 +1791,11 @@ func_run_hooks ()
 #        usage_message=$usage_message'
 #      -s, --silent       don'\''t print informational messages
 #    '
-#
-#        func_quote_for_eval ${1+"$@"}
-#        my_options_prep_result=$func_quote_for_eval_result
+#        # No change in '$@' (ignored completely by this hook).  There is
+#        # no need to do the equivalent (but slower) action:
+#        # func_quote_for_eval ${1+"$@"}
+#        # my_options_prep_result=$func_quote_for_eval_result
+#        false
 #    }
 #    func_add_hook func_options_prep my_options_prep
 #
@@ -1794,25 +1804,37 @@ func_run_hooks ()
 #    {
 #        $debug_cmd
 #
+#        args_changed=false
+#
 #        # Note that for efficiency, we parse as many options as we can
 #        # recognise in a loop before passing the remainder back to the
 #        # caller on the first unrecognised argument we encounter.
 #        while test $# -gt 0; do
 #          opt=$1; shift
 #          case $opt in
-#            --silent|-s) opt_silent=: ;;
+#            --silent|-s) opt_silent=:
+#                         args_changed=:
+#                         ;;
 #            # Separate non-argument short options:
 #            -s*)         func_split_short_opt "$_G_opt"
 #                         set dummy "$func_split_short_opt_name" \
 #                             "-$func_split_short_opt_arg" ${1+"$@"}
 #                         shift
+#                         args_changed=:
 #                         ;;
-#            *)            set dummy "$_G_opt" "$*"; shift; break ;;
+#            *)           # Make sure the first unrecognised option "$_G_opt"
+#                         # is added back to "$@", we could need that later
+#                         # if $args_changed is true.
+#                         set dummy "$_G_opt" ${1+"$@"}; shift; break ;;
 #          esac
 #        done
 #
-#        func_quote_for_eval ${1+"$@"}
-#        my_silent_option_result=$func_quote_for_eval_result
+#        if $args_changed; then
+#          func_quote_for_eval ${1+"$@"}
+#          my_silent_option_result=$func_quote_for_eval_result
+#        fi
+#
+#        $args_changed
 #    }
 #    func_add_hook func_parse_options my_silent_option
 #
@@ -1824,16 +1846,32 @@ func_run_hooks ()
 #        $opt_silent && $opt_verbose && func_fatal_help "\
 #    '--silent' and '--verbose' options are mutually exclusive."
 #
-#        func_quote_for_eval ${1+"$@"}
-#        my_option_validation_result=$func_quote_for_eval_result
+#        false
 #    }
 #    func_add_hook func_validate_options my_option_validation
 #
-# You'll alse need to manually amend $usage_message to reflect the extra
+# You'll also need to manually amend $usage_message to reflect the extra
 # options you parse.  It's preferable to append if you can, so that
 # multiple option parsing hooks can be added safely.

+# func_options_finish [ARG]...
+# ----------------------------
+# Finishing the option parse loop (call 'func_options' hooks ATM).
+func_options_finish ()
+{
+    $debug_cmd
+
+    _G_func_options_finish_exit=false
+    if func_run_hooks func_options ${1+"$@"}; then
+      func_options_finish_result=$func_run_hooks_result
+      _G_func_options_finish_exit=:
+    fi
+
+    $_G_func_options_finish_exit
+}
+
+
 # func_options [ARG]...
 # ---------------------
 # All the functions called inside func_options are hookable. See the
@@ -1843,17 +1881,28 @@ func_options ()
 {
     $debug_cmd
 
-    func_options_prep ${1+"$@"}
-    eval func_parse_options \
-        ${func_options_prep_result+"$func_options_prep_result"}
-    eval func_validate_options \
-        ${func_parse_options_result+"$func_parse_options_result"}
+    _G_rc_options=false
 
-    eval func_run_hooks func_options \
-        ${func_validate_options_result+"$func_validate_options_result"}
+    for my_func in options_prep parse_options validate_options options_finish
+    do
+      if eval func_$my_func '${1+"$@"}'; then
+        eval _G_res_var='$'"func_${my_func}_result"
+        eval set dummy "$_G_res_var" ; shift
+        _G_rc_options=:
+      fi
+    done
 
-    # save modified positional parameters for caller
-    func_options_result=$func_run_hooks_result
+    # Save modified positional parameters for caller.  As a top-level
+    # options-parser function we always need to set the 'func_options_result'
+    # variable (regardless the $_G_rc_options value).
+    if $_G_rc_options; then
+      func_options_result=$_G_res_var
+    else
+      func_quote_for_eval ${1+"$@"}
+      func_options_result=$func_quote_for_eval_result
+    fi
+
+    $_G_rc_options
 }

@@ -1862,9 +1911,9 @@ func_options ()
 # All initialisations required before starting the option parse loop.
 # Note that when calling hook functions, we pass through the list of
 # positional parameters.  If a hook function modifies that list, and
-# needs to propogate that back to rest of this script, then the complete
+# needs to propagate that back to rest of this script, then the complete
 # modified list must be put in 'func_run_hooks_result' before
-# returning.
+# returning $EXIT_SUCCESS (otherwise $EXIT_FAILURE is returned).
 func_hookable func_options_prep
 func_options_prep ()
 {
@@ -1874,10 +1923,14 @@ func_options_prep ()
     opt_verbose=false
     opt_warning_types=
 
-    func_run_hooks func_options_prep ${1+"$@"}
+    _G_rc_options_prep=false
+    if func_run_hooks func_options_prep ${1+"$@"}; then
+      _G_rc_options_prep=:
+      # save modified positional parameters for caller
+      func_options_prep_result=$func_run_hooks_result
+    fi
 
-    # save modified positional parameters for caller
-    func_options_prep_result=$func_run_hooks_result
+    $_G_rc_options_prep
 }

@@ -1891,18 +1944,20 @@ func_parse_options ()
 
     func_parse_options_result=
 
+    _G_rc_parse_options=false
     # this just eases exit handling
     while test $# -gt 0; do
       # Defer to hook functions for initial option parsing, so they
       # get priority in the event of reusing an option name.
-      func_run_hooks func_parse_options ${1+"$@"}
-
-      # Adjust func_parse_options positional parameters to match
-      eval set dummy "$func_run_hooks_result"; shift
+      if func_run_hooks func_parse_options ${1+"$@"}; then
+        eval set dummy "$func_run_hooks_result"; shift
+        _G_rc_parse_options=:
+      fi
 
       # Break out of the loop if we already parsed every option.
       test $# -gt 0 || break
 
+      _G_match_parse_options=:
       _G_opt=$1
       shift
       case $_G_opt in
@@ -1917,7 +1972,10 @@ func_parse_options ()
 		      ;;
 
         --warnings|--warning|-W)
-                      test $# = 0 && func_missing_arg $_G_opt && break
+                      if test $# = 0 && func_missing_arg $_G_opt; then
+                        _G_rc_parse_options=:
+                        break
+                      fi
                       case " $warning_categories $1" in
                         *" $1 "*)
                           # trailing space prevents matching last $1 above
@@ -1970,15 +2028,25 @@ func_parse_options ()
                       shift
                       ;;
 
-        --)           break ;;
+        --)           _G_rc_parse_options=: ; break ;;
         -*)           func_fatal_help "unrecognised option: '$_G_opt'" ;;
-        *)            set dummy "$_G_opt" ${1+"$@"}; shift; break ;;
+        *)            set dummy "$_G_opt" ${1+"$@"}; shift
+                      _G_match_parse_options=false
+                      break
+                      ;;
       esac
+
+      $_G_match_parse_options && _G_rc_parse_options=:
     done
 
-    # save modified positional parameters for caller
-    func_quote_for_eval ${1+"$@"}
-    func_parse_options_result=$func_quote_for_eval_result
+
+    if $_G_rc_parse_options; then
+      # save modified positional parameters for caller
+      func_quote_for_eval ${1+"$@"}
+      func_parse_options_result=$func_quote_for_eval_result
+    fi
+
+    $_G_rc_parse_options
 }

@@ -1991,16 +2059,21 @@ func_validate_options ()
 {
     $debug_cmd
 
+    _G_rc_validate_options=false
+
     # Display all warnings if -W was not given.
     test -n "$opt_warning_types" || opt_warning_types=" $warning_categories"
 
-    func_run_hooks func_validate_options ${1+"$@"}
+    if func_run_hooks func_validate_options ${1+"$@"}; then
+      # save modified positional parameters for caller
+      func_validate_options_result=$func_run_hooks_result
+      _G_rc_validate_options=:
+    fi
 
     # Bail if the options were screwed!
     $exit_cmd $EXIT_FAILURE
 
-    # save modified positional parameters for caller
-    func_validate_options_result=$func_run_hooks_result
+    $_G_rc_validate_options
 }

diff --git a/build-aux/ltmain.in b/build-aux/ltmain.in
index 24acefd..b4c6bcd 100644
--- a/build-aux/ltmain.in
+++ b/build-aux/ltmain.in
@@ -358,6 +358,8 @@ libtool_options_prep ()
     nonopt=
     preserve_args=
 
+    _G_rc_lt_options_prep=:
+
     # Shorthand for --mode=foo, only valid as the first argument
     case $1 in
     clean|clea|cle|cl)
@@ -381,11 +383,18 @@ libtool_options_prep ()
     uninstall|uninstal|uninsta|uninst|unins|unin|uni|un|u)
       shift; set dummy --mode uninstall ${1+"$@"}; shift
       ;;
+    *)
+      _G_rc_lt_options_prep=false
+      ;;
     esac
 
-    # Pass back the list of options.
-    func_quote_for_eval ${1+"$@"}
-    libtool_options_prep_result=$func_quote_for_eval_result
+    if $_G_rc_lt_options_prep; then
+      # Pass back the list of options.
+      func_quote_for_eval ${1+"$@"}
+      libtool_options_prep_result=$func_quote_for_eval_result
+    fi
+
+    $_G_rc_lt_options_prep
 }
 func_add_hook func_options_prep libtool_options_prep
 
@@ -397,9 +406,12 @@ libtool_parse_options ()
 {
     $debug_cmd
 
+    _G_rc_lt_parse_options=false
+
     # Perform our own loop to consume as many options as possible in
     # each iteration.
     while test $# -gt 0; do
+      _G_match_lt_parse_options=:
       _G_opt=$1
       shift
       case $_G_opt in
@@ -474,15 +486,22 @@ libtool_parse_options ()
                         func_append preserve_args " $_G_opt"
                         ;;
 
-	# An option not handled by this hook function:
-        *)		set dummy "$_G_opt" ${1+"$@"};	shift; break  ;;
+        # An option not handled by this hook function:
+        *)              set dummy "$_G_opt" ${1+"$@"} ; shift
+                        _G_match_lt_parse_options=false
+                        break
+                        ;;
       esac
+      $_G_match_lt_parse_options && _G_rc_lt_parse_options=:
     done
 
+    if $_G_rc_lt_parse_options; then
+      # save modified positional parameters for caller
+      func_quote_for_eval ${1+"$@"}
+      libtool_parse_options_result=$func_quote_for_eval_result
+    fi
 
-    # save modified positional parameters for caller
-    func_quote_for_eval ${1+"$@"}
-    libtool_parse_options_result=$func_quote_for_eval_result
+    $_G_rc_lt_parse_options
 }
 func_add_hook func_parse_options libtool_parse_options
 
diff --git a/gl/build-aux/options-parser b/gl/build-aux/options-parser
index d651f1d..4c7e9cb 100644
--- a/gl/build-aux/options-parser
+++ b/gl/build-aux/options-parser
@@ -1,7 +1,7 @@
 #! /bin/sh
 
 # Set a version string for this script.
-scriptversion=2014-01-07.03; # UTC
+scriptversion=2015-10-07.11; # UTC
 
 # A portable, pluggable option parser for Bourne shell.
 # Written by Gary V. Vaughan, 2010
@@ -161,6 +161,8 @@ func_run_hooks ()
 {
     $debug_cmd
 
+    _G_rc_run_hooks=false
+
     case " $hookable_fns " in
       *" $1 "*) ;;
       *) func_fatal_error "'$1' does not support hook funcions.n" ;;
@@ -169,16 +171,16 @@ func_run_hooks ()
     eval _G_hook_fns=\$$1_hooks; shift
 
     for _G_hook in $_G_hook_fns; do
-      eval $_G_hook '"$@"'
-
-      # store returned options list back into positional
-      # parameters for next 'cmd' execution.
-      eval _G_hook_result=\$${_G_hook}_result
-      eval set dummy "$_G_hook_result"; shift
+      if eval $_G_hook '"$@"'; then
+        # store returned options list back into positional
+        # parameters for next 'cmd' execution.
+        eval _G_hook_result=\$${_G_hook}_result
+        eval set dummy "$_G_hook_result"; shift
+        _G_rc_run_hooks=:
+      fi
     done
 
-    func_quote_for_eval ${1+"$@"}
-    func_run_hooks_result=$func_quote_for_eval_result
+    $_G_rc_run_hooks && func_run_hooks_result=$_G_hook_result
 }

@@ -188,10 +190,16 @@ func_run_hooks ()
 ## --------------- ##
 
 # In order to add your own option parsing hooks, you must accept the
-# full positional parameter list in your hook function, remove any
-# options that you action, and then pass back the remaining unprocessed
+# full positional parameter list in your hook function, you may remove/edit
+# any options that you action, and then pass back the remaining unprocessed
 # options in '<hooked_function_name>_result', escaped suitably for
-# 'eval'.  Like this:
+# 'eval'.  In this case you also must return $EXIT_SUCCESS to let the
+# hook's caller know that it should pay attention to
+# '<hooked_function_name>_result'.  Returning $EXIT_FAILURE signalizes that
+# arguments are left untouched by the hook and therefore caller will ignore the
+# result variable.
+#
+# Like this:
 #
 #    my_options_prep ()
 #    {
@@ -201,9 +209,11 @@ func_run_hooks ()
 #        usage_message=$usage_message'
 #      -s, --silent       don'\''t print informational messages
 #    '
-#
-#        func_quote_for_eval ${1+"$@"}
-#        my_options_prep_result=$func_quote_for_eval_result
+#        # No change in '$@' (ignored completely by this hook).  There is
+#        # no need to do the equivalent (but slower) action:
+#        # func_quote_for_eval ${1+"$@"}
+#        # my_options_prep_result=$func_quote_for_eval_result
+#        false
 #    }
 #    func_add_hook func_options_prep my_options_prep
 #
@@ -212,25 +222,37 @@ func_run_hooks ()
 #    {
 #        $debug_cmd
 #
+#        args_changed=false
+#
 #        # Note that for efficiency, we parse as many options as we can
 #        # recognise in a loop before passing the remainder back to the
 #        # caller on the first unrecognised argument we encounter.
 #        while test $# -gt 0; do
 #          opt=$1; shift
 #          case $opt in
-#            --silent|-s) opt_silent=: ;;
+#            --silent|-s) opt_silent=:
+#                         args_changed=:
+#                         ;;
 #            # Separate non-argument short options:
 #            -s*)         func_split_short_opt "$_G_opt"
 #                         set dummy "$func_split_short_opt_name" \
 #                             "-$func_split_short_opt_arg" ${1+"$@"}
 #                         shift
+#                         args_changed=:
 #                         ;;
-#            *)            set dummy "$_G_opt" "$*"; shift; break ;;
+#            *)           # Make sure the first unrecognised option "$_G_opt"
+#                         # is added back to "$@", we could need that later
+#                         # if $args_changed is true.
+#                         set dummy "$_G_opt" ${1+"$@"}; shift; break ;;
 #          esac
 #        done
 #
-#        func_quote_for_eval ${1+"$@"}
-#        my_silent_option_result=$func_quote_for_eval_result
+#        if $args_changed; then
+#          func_quote_for_eval ${1+"$@"}
+#          my_silent_option_result=$func_quote_for_eval_result
+#        fi
+#
+#        $args_changed
 #    }
 #    func_add_hook func_parse_options my_silent_option
 #
@@ -242,16 +264,32 @@ func_run_hooks ()
 #        $opt_silent && $opt_verbose && func_fatal_help "\
 #    '--silent' and '--verbose' options are mutually exclusive."
 #
-#        func_quote_for_eval ${1+"$@"}
-#        my_option_validation_result=$func_quote_for_eval_result
+#        false
 #    }
 #    func_add_hook func_validate_options my_option_validation
 #
-# You'll alse need to manually amend $usage_message to reflect the extra
+# You'll also need to manually amend $usage_message to reflect the extra
 # options you parse.  It's preferable to append if you can, so that
 # multiple option parsing hooks can be added safely.

+# func_options_finish [ARG]...
+# ----------------------------
+# Finishing the option parse loop (call 'func_options' hooks ATM).
+func_options_finish ()
+{
+    $debug_cmd
+
+    _G_func_options_finish_exit=false
+    if func_run_hooks func_options ${1+"$@"}; then
+      func_options_finish_result=$func_run_hooks_result
+      _G_func_options_finish_exit=:
+    fi
+
+    $_G_func_options_finish_exit
+}
+
+
 # func_options [ARG]...
 # ---------------------
 # All the functions called inside func_options are hookable. See the
@@ -261,17 +299,28 @@ func_options ()
 {
     $debug_cmd
 
-    func_options_prep ${1+"$@"}
-    eval func_parse_options \
-        ${func_options_prep_result+"$func_options_prep_result"}
-    eval func_validate_options \
-        ${func_parse_options_result+"$func_parse_options_result"}
+    _G_rc_options=false
 
-    eval func_run_hooks func_options \
-        ${func_validate_options_result+"$func_validate_options_result"}
+    for my_func in options_prep parse_options validate_options options_finish
+    do
+      if eval func_$my_func '${1+"$@"}'; then
+        eval _G_res_var='$'"func_${my_func}_result"
+        eval set dummy "$_G_res_var" ; shift
+        _G_rc_options=:
+      fi
+    done
 
-    # save modified positional parameters for caller
-    func_options_result=$func_run_hooks_result
+    # Save modified positional parameters for caller.  As a top-level
+    # options-parser function we always need to set the 'func_options_result'
+    # variable (regardless the $_G_rc_options value).
+    if $_G_rc_options; then
+      func_options_result=$_G_res_var
+    else
+      func_quote_for_eval ${1+"$@"}
+      func_options_result=$func_quote_for_eval_result
+    fi
+
+    $_G_rc_options
 }

@@ -280,9 +329,9 @@ func_options ()
 # All initialisations required before starting the option parse loop.
 # Note that when calling hook functions, we pass through the list of
 # positional parameters.  If a hook function modifies that list, and
-# needs to propogate that back to rest of this script, then the complete
+# needs to propagate that back to rest of this script, then the complete
 # modified list must be put in 'func_run_hooks_result' before
-# returning.
+# returning $EXIT_SUCCESS (otherwise $EXIT_FAILURE is returned).
 func_hookable func_options_prep
 func_options_prep ()
 {
@@ -292,10 +341,14 @@ func_options_prep ()
     opt_verbose=false
     opt_warning_types=
 
-    func_run_hooks func_options_prep ${1+"$@"}
+    _G_rc_options_prep=false
+    if func_run_hooks func_options_prep ${1+"$@"}; then
+      _G_rc_options_prep=:
+      # save modified positional parameters for caller
+      func_options_prep_result=$func_run_hooks_result
+    fi
 
-    # save modified positional parameters for caller
-    func_options_prep_result=$func_run_hooks_result
+    $_G_rc_options_prep
 }

@@ -309,18 +362,20 @@ func_parse_options ()
 
     func_parse_options_result=
 
+    _G_rc_parse_options=false
     # this just eases exit handling
     while test $# -gt 0; do
       # Defer to hook functions for initial option parsing, so they
       # get priority in the event of reusing an option name.
-      func_run_hooks func_parse_options ${1+"$@"}
-
-      # Adjust func_parse_options positional parameters to match
-      eval set dummy "$func_run_hooks_result"; shift
+      if func_run_hooks func_parse_options ${1+"$@"}; then
+        eval set dummy "$func_run_hooks_result"; shift
+        _G_rc_parse_options=:
+      fi
 
       # Break out of the loop if we already parsed every option.
       test $# -gt 0 || break
 
+      _G_match_parse_options=:
       _G_opt=$1
       shift
       case $_G_opt in
@@ -335,7 +390,10 @@ func_parse_options ()
 		      ;;
 
         --warnings|--warning|-W)
-                      test $# = 0 && func_missing_arg $_G_opt && break
+                      if test $# = 0 && func_missing_arg $_G_opt; then
+                        _G_rc_parse_options=:
+                        break
+                      fi
                       case " $warning_categories $1" in
                         *" $1 "*)
                           # trailing space prevents matching last $1 above
@@ -388,15 +446,25 @@ func_parse_options ()
                       shift
                       ;;
 
-        --)           break ;;
+        --)           _G_rc_parse_options=: ; break ;;
         -*)           func_fatal_help "unrecognised option: '$_G_opt'" ;;
-        *)            set dummy "$_G_opt" ${1+"$@"}; shift; break ;;
+        *)            set dummy "$_G_opt" ${1+"$@"}; shift
+                      _G_match_parse_options=false
+                      break
+                      ;;
       esac
+
+      $_G_match_parse_options && _G_rc_parse_options=:
     done
 
-    # save modified positional parameters for caller
-    func_quote_for_eval ${1+"$@"}
-    func_parse_options_result=$func_quote_for_eval_result
+
+    if $_G_rc_parse_options; then
+      # save modified positional parameters for caller
+      func_quote_for_eval ${1+"$@"}
+      func_parse_options_result=$func_quote_for_eval_result
+    fi
+
+    $_G_rc_parse_options
 }

@@ -409,16 +477,21 @@ func_validate_options ()
 {
     $debug_cmd
 
+    _G_rc_validate_options=false
+
     # Display all warnings if -W was not given.
     test -n "$opt_warning_types" || opt_warning_types=" $warning_categories"
 
-    func_run_hooks func_validate_options ${1+"$@"}
+    if func_run_hooks func_validate_options ${1+"$@"}; then
+      # save modified positional parameters for caller
+      func_validate_options_result=$func_run_hooks_result
+      _G_rc_validate_options=:
+    fi
 
     # Bail if the options were screwed!
     $exit_cmd $EXIT_FAILURE
 
-    # save modified positional parameters for caller
-    func_validate_options_result=$func_run_hooks_result
+    $_G_rc_validate_options
 }

-- 
2.5.0

>From 5762e2c82e53b6dd712f19985c90081684263810 Mon Sep 17 00:00:00 2001
From: Pavel Raiskup <[email-masked]>
Date: Sun, 11 Oct 2015 14:35:15 +0200
Subject: [PATCH 3/3] funclib: refactor quoting methods a bit

>From now we have two basic functions to perform string quoting for
shell evaluation -- 'func_quote_arg' to quote one argument and
'func_quote' which takes list of arguments to be quoted.

New function name-scheme should be more descriptive (previously we
called func_quote_for_eval with one argument and also multiple
arguments, while we had confusing
$func_quote_for_eval_unquoted_result which is redundant for
multiple-arguments call).

New abstraction allowed us (in an easy way) to implement
bash-specific optimization for quoting  (using
'printf -v VARNAME %q "$value"', suggested by Eric Blake), this
construct may be used on those places where we don't care much
about the result aesthetics (its thus not useful for '*.la'
generation or for error printing).

* gl/build-aux/funclib.sh (func_append_quoted): Use
func_quote_arg internally (kept in 'pretty' mode for now).
(func_quote): Made to be "main" high-level quoting method taking
list of arguments to be quoted into single command.  It replaces
func_quote_for_{expand,eval}.
(func_quote_portable): Implements quoting in shell, falling back
to portable sed call (rare cases).
(func_quotefast_eval): New internal function using fast
bash-specific construct, falling back to func_quote_portable for
non-Bash scripts.
(func_quote_arg): New function to quote one argument.
(func_quote_for_eval): Removed.  All callers changed to call
func_quote.
(func_quote_for_expand): Likewise.
* bootstrap: Sync with funclib.sh and options-parser.
---
 bootstrap                   | 327 +++++++++++++++++++++++++-------------------
 build-aux/ltmain.in         | 114 +++++++--------
 gl/build-aux/bootstrap.in   |  22 +--
 gl/build-aux/funclib.sh     | 279 +++++++++++++++++++++----------------
 gl/build-aux/options-parser |  18 +--
 gl/doc/bootstrap.texi       |   4 +-
 libtoolize.in               |  18 +--
 7 files changed, 440 insertions(+), 342 deletions(-)

diff --git a/bootstrap b/bootstrap
index 4f00096..1d86ab0 100755
--- a/bootstrap
+++ b/bootstrap
@@ -230,7 +230,7 @@ vc_ignore=
 
 # Source required external libraries:
 # Set a version string for this script.
-scriptversion=2015-10-04.22; # UTC
+scriptversion=2015-10-12.13; # UTC
 
 # General shell script boiler plate, and helper functions.
 # Written by Gary V. Vaughan, 2004
@@ -746,16 +746,16 @@ if test yes = "$_G_HAVE_PLUSEQ_OP"; then
   {
     $debug_cmd
 
-    func_quote_for_eval "$2"
-    eval "$1+=\\ \$func_quote_for_eval_result"
+    func_quote_arg pretty "$2"
+    eval "$1+=\\ \$func_quote_arg_result"
   }'
 else
   func_append_quoted ()
   {
     $debug_cmd
 
-    func_quote_for_eval "$2"
-    eval "$1=\$$1\\ \$func_quote_for_eval_result"
+    func_quote_arg pretty "$2"
+    eval "$1=\$$1\\ \$func_quote_arg_result"
   }
 fi
 
@@ -1257,132 +1257,181 @@ func_relative_path ()
 }

-# func_quote ARG
-# --------------
-# Aesthetically quote one ARG, store the result into $func_quote_result.  Note
-# that we keep attention to performance here (so far O(N) complexity as long as
-# func_append is O(1)).
-func_quote ()
+# func_quote_portable EVAL ARG
+# ----------------------------
+# Internal function to portably implement func_quote_arg.  Note that we still
+# keep attention to performance here so we as much as possible try to avoid
+# calling sed binary (so far O(N) complexity as long as func_append is O(1)).
+func_quote_portable ()
 {
     $debug_cmd
 
-    func_quote_result=$1
+    func_quote_portable_result=$2
 
-    case $func_quote_result in
-      *[\\\`\"\$]*)
-        case $func_quote_result in
-          *'*'*|*'['*)
-            func_quote_result=`$ECHO "$func_quote_result" | $SED "$sed_quote_subst"`
-            return 0
-            ;;
-        esac
+    # one-time-loop (easy break)
+    while true
+    do
+      if $1; then
+        func_quote_portable_result=`$ECHO "$2" | $SED \
+          -e "$sed_double_quote_subst" -e "$sed_double_backslash"`
+        break
+      fi
 
-        func_quote_old_IFS=$IFS
-        for _G_char in '\' '`' '"' '$'
-        do
-          # STATE($1) PREV($2) SEPARATOR($3)
-          set start "" ""
-          func_quote_result=dummy"$_G_char$func_quote_result$_G_char"dummy
-          IFS=$_G_char
-          for _G_part in $func_quote_result
+      # Quote for eval.
+      case $func_quote_portable_result in
+        *[\\\`\"\$]*)
+          case $func_quote_portable_result in
+            *[\[\*\?]*)
+              func_quote_portable_result=`$ECHO "$func_quote_portable_result" | $SED "$sed_quote_subst"`
+              break
+              ;;
+          esac
+
+          func_quote_portable_old_IFS=$IFS
+          for _G_char in '\' '`' '"' '$'
           do
-            case $1 in
-            quote)
-              func_append func_quote_result "$3$2"
-              set quote "$_G_part" "\\$_G_char"
-              ;;
-            start)
-              set first "" ""
-              func_quote_result=
-              ;;
-            first)
-              set quote "$_G_part" ""
-              ;;
-            esac
+            # STATE($1) PREV($2) SEPARATOR($3)
+            set start "" ""
+            func_quote_portable_result=dummy"$_G_char$func_quote_portable_result$_G_char"dummy
+            IFS=$_G_char
+            for _G_part in $func_quote_portable_result
+            do
+              case $1 in
+              quote)
+                func_append func_quote_portable_result "$3$2"
+                set quote "$_G_part" "\\$_G_char"
+                ;;
+              start)
+                set first "" ""
+                func_quote_portable_result=
+                ;;
+              first)
+                set quote "$_G_part" ""
+                ;;
+              esac
+            done
           done
-          IFS=$func_quote_old_IFS
-        done
-        ;;
-      *) ;;
-    esac
-}
-
-
-# func_quote_for_eval ARG...
-# --------------------------
-# Aesthetically quote ARGs to be evaled later.
-# This function returns two values:
-#   i) func_quote_for_eval_result
-#      double-quoted, suitable for a subsequent eval
-#  ii) func_quote_for_eval_unquoted_result
-#      has all characters that are still active within double
-#      quotes backslashified.
-func_quote_for_eval ()
-{
-    $debug_cmd
-
-    func_quote_for_eval_unquoted_result=
-    func_quote_for_eval_result=
-    while test 0 -lt $#; do
-      func_quote "$1"
-      _G_unquoted_arg=$func_quote_result
-      if test -n "$func_quote_for_eval_unquoted_result"; then
-	func_append func_quote_for_eval_unquoted_result " $_G_unquoted_arg"
-      else
-        func_append func_quote_for_eval_unquoted_result "$_G_unquoted_arg"
-      fi
-
-      case $_G_unquoted_arg in
-        # Double-quote args containing shell metacharacters to delay
-        # word splitting, command substitution and variable expansion
-        # for a subsequent eval.
-        # Many Bourne shells cannot handle close brackets correctly
-        # in scan sets, so we specify it separately.
-        *[\[\~\#\^\&\*\(\)\{\}\|\;\<\>\?\'\ \	]*|*]*|"")
-          _G_quoted_arg=\"$_G_unquoted_arg\"
+          IFS=$func_quote_portable_old_IFS
           ;;
-        *)
-          _G_quoted_arg=$_G_unquoted_arg
-	  ;;
+        *) ;;
       esac
-
-      if test -n "$func_quote_for_eval_result"; then
-	func_append func_quote_for_eval_result " $_G_quoted_arg"
-      else
-        func_append func_quote_for_eval_result "$_G_quoted_arg"
-      fi
-      shift
+      break
     done
-}
 
-
-# func_quote_for_expand ARG
-# -------------------------
-# Aesthetically quote ARG to be evaled later; same as above,
-# but do not quote variable references.
-func_quote_for_expand ()
-{
-    $debug_cmd
-
-    case $1 in
-      *[\\\`\"]*)
-	_G_arg=`$ECHO "$1" | $SED \
-	    -e "$sed_double_quote_subst" -e "$sed_double_backslash"` ;;
-      *)
-        _G_arg=$1 ;;
-    esac
-
-    case $_G_arg in
-      # Double-quote args containing shell metacharacters to delay
-      # word splitting and command substitution for a subsequent eval.
-      # Many Bourne shells cannot handle close brackets correctly
+    func_quote_portable_unquoted_result=$func_quote_portable_result
+    case $func_quote_portable_result in
+      # double-quote args containing shell metacharacters to delay
+      # word splitting, command substitution and variable expansion
+      # for a subsequent eval.
+      # many bourne shells cannot handle close brackets correctly
       # in scan sets, so we specify it separately.
       *[\[\~\#\^\&\*\(\)\{\}\|\;\<\>\?\'\ \	]*|*]*|"")
-        _G_arg=\"$_G_arg\"
+        func_quote_portable_result=\"$func_quote_portable_result\"
         ;;
     esac
+}
 
-    func_quote_for_expand_result=$_G_arg
+
+# func_quotefast_eval ARG
+# -----------------------
+# Quote one ARG (internal).  This is equivalent to 'func_quote_arg eval ARG',
+# but optimized for speed.  Result is stored in $func_quotefast_eval.
+if test xyes = `(x=; printf -v x %q yes; echo x"$x") 2>/dev/null`; then
+  func_quotefast_eval ()
+  {
+    printf -v func_quotefast_eval_result %q "$1"
+  }
+else
+  func_quotefast_eval ()
+  {
+    func_quote_portable false "$1"
+    func_quotefast_eval_result=$func_quote_portable_result
+  }
+fi
+
+
+# func_quote_arg MODEs ARG
+# ------------------------
+# Quote one ARG to be evaled later.  MODEs argument may contain zero ore more
+# specifiers listed below separated by ',' character.  This function returns two
+# values:
+#   i) func_quote_arg_result
+#      double-quoted (when needed), suitable for a subsequent eval
+#  ii) func_quote_arg_unquoted_result
+#      has all characters that are still active within double
+#      quotes backslashified.  Available only if 'unquoted' is specified.
+#
+# Available modes:
+# ----------------
+# 'eval' (default)
+#       - escape shell special characters
+# 'expand'
+#       - the same as 'eval';  but do not quote variable references
+# 'pretty'
+#       - request aesthetic output, i.e. '"a b"' instead of 'a\ b'.  This might
+#         later used in func_quote to get output like: 'echo "a b"' instead of
+#         'echo a\ b'.  This is slower than default on some shells.
+# 'unquoted'
+#       - produce also $func_quote_arg_unquoted_result which does not contain
+#         wrapping double-quotes.
+#
+# Examples for 'func_quote_arg pretty,unquoted string':
+#
+#   string      | *_result              | *_unquoted_result
+#   ------------+-----------------------+-------------------
+#   "           | \"                    | \"
+#   a b         | "a b"                 | a b
+#   "a b"       | "\"a b\""             | \"a b\"
+#   *           | "*"                   | *
+#   z="${x-$y}" | "z=\"\${x-\$y}\""     | z=\"\${x-\$y}\"
+#
+# Examples for 'func_quote_arg pretty,unquoted,expand string':
+#
+#   string        |   *_result          |  *_unquoted_result
+#   --------------+---------------------+--------------------
+#   z="${x-$y}"   | "z=\"${x-$y}\""     | z=\"${x-$y}\"
+func_quote_arg ()
+{
+    _G_quote_expand=false
+    case ,$1, in
+      *,expand,*)
+        _G_quote_expand=:
+        ;;
+    esac
+
+    case ,$1, in
+      *,pretty,*|*,expand,*|*,unquoted,*)
+        func_quote_portable $_G_quote_expand "$2"
+        func_quote_arg_result=$func_quote_portable_result
+        func_quote_arg_unquoted_result=$func_quote_portable_unquoted_result
+        ;;
+      *)
+        # Faster quote-for-eval for some shells.
+        func_quotefast_eval "$2"
+        func_quote_arg_result=$func_quotefast_eval_result
+        ;;
+    esac
+}
+
+
+# func_quote MODEs ARGs...
+# ------------------------
+# Quote all ARGs to be evaled later and join them into single command.  See
+# func_quote_arg's description for more info.
+func_quote ()
+{
+    $debug_cmd
+    _G_func_quote_mode=$1 ; shift
+    func_quote_result=
+    while test 0 -lt $#; do
+      func_quote_arg "$_G_func_quote_mode" "$1"
+      if test -n "$func_quote_result"; then
+        func_append func_quote_result " $func_quote_arg_result"
+      else
+        func_append func_quote_result "$func_quote_arg_result"
+      fi
+      shift
+    done
 }

@@ -1428,8 +1477,8 @@ func_show_eval ()
     _G_cmd=$1
     _G_fail_exp=${2-':'}
 
-    func_quote_for_expand "$_G_cmd"
-    eval "func_notquiet $func_quote_for_expand_result"
+    func_quote_arg pretty,expand "$_G_cmd"
+    eval "func_notquiet $func_quote_arg_result"
 
     $opt_dry_run || {
       eval "$_G_cmd"
@@ -1454,8 +1503,8 @@ func_show_eval_locale ()
     _G_fail_exp=${2-':'}
 
     $opt_quiet || {
-      func_quote_for_expand "$_G_cmd"
-      eval "func_echo $func_quote_for_expand_result"
+      func_quote_arg expand,pretty "$_G_cmd"
+      eval "func_echo $func_quote_arg_result"
     }
 
     $opt_dry_run || {
@@ -1583,7 +1632,7 @@ func_lt_ver ()
 #! /bin/sh
 
 # Set a version string for this script.
-scriptversion=2015-10-07.11; # UTC
+scriptversion=2015-10-12.13; # UTC
 
 # A portable, pluggable option parser for Bourne shell.
 # Written by Gary V. Vaughan, 2010
@@ -1793,8 +1842,8 @@ func_run_hooks ()
 #    '
 #        # No change in '$@' (ignored completely by this hook).  There is
 #        # no need to do the equivalent (but slower) action:
-#        # func_quote_for_eval ${1+"$@"}
-#        # my_options_prep_result=$func_quote_for_eval_result
+#        # func_quote eval ${1+"$@"}
+#        # my_options_prep_result=$func_quote_result
 #        false
 #    }
 #    func_add_hook func_options_prep my_options_prep
@@ -1830,8 +1879,8 @@ func_run_hooks ()
 #        done
 #
 #        if $args_changed; then
-#          func_quote_for_eval ${1+"$@"}
-#          my_silent_option_result=$func_quote_for_eval_result
+#          func_quote eval ${1+"$@"}
+#          my_silent_option_result=$func_quote_result
 #        fi
 #
 #        $args_changed
@@ -1898,8 +1947,8 @@ func_options ()
     if $_G_rc_options; then
       func_options_result=$_G_res_var
     else
-      func_quote_for_eval ${1+"$@"}
-      func_options_result=$func_quote_for_eval_result
+      func_quote eval ${1+"$@"}
+      func_options_result=$func_quote_result
     fi
 
     $_G_rc_options
@@ -2042,8 +2091,8 @@ func_parse_options ()
 
     if $_G_rc_parse_options; then
       # save modified positional parameters for caller
-      func_quote_for_eval ${1+"$@"}
-      func_parse_options_result=$func_quote_for_eval_result
+      func_quote eval ${1+"$@"}
+      func_parse_options_result=$func_quote_result
     fi
 
     $_G_rc_parse_options
@@ -2753,7 +2802,7 @@ test extract-trace = "$progname" && func_main "$@"
 # End:
 
 # Set a version string for *this* script.
-scriptversion=2015-01-20.17; # UTC
+scriptversion=2015-10-12.13; # UTC

 ## ------------------- ##
@@ -2781,8 +2830,8 @@ func_bootstrap ()
 
     # Save the current positional parameters to prevent them being
     # corrupted by calls to 'set' in 'func_init'.
-    func_quote_for_eval ${1+"$@"}
-    _G_saved_positional_parameters=$func_quote_for_eval_result
+    func_quote eval ${1+"$@"}
+    _G_saved_positional_parameters=$func_quote_result
 
     # Initialisation.
     func_init
@@ -4821,8 +4870,8 @@ func_show_eval ()
     _G_fail_exp=${2-':'}
 
     ${opt_silent-'false'} || {
-      func_quote_for_eval $_G_cmd
-      eval func_truncate_cmd $func_quote_for_eval_result
+      func_quote eval $_G_cmd
+      eval func_truncate_cmd $func_quote_result
       func_echo "running: $tc_bold$func_truncate_cmd_result$tc_reset"
     }
 
@@ -5209,8 +5258,8 @@ bootstrap_options_prep ()
     opt_skip_po=false
 
     # Pass back the list of options we consumed.
-    func_quote_for_eval ${1+"$@"}
-    bootstrap_options_prep_result=$func_quote_for_eval_result
+    func_quote eval ${1+"$@"}
+    bootstrap_options_prep_result=$func_quote_result
 }
 func_add_hook func_options_prep bootstrap_options_prep
 
@@ -5260,8 +5309,8 @@ bootstrap_parse_options ()
     done
 
     # save modified positional parameters for caller
-    func_quote_for_eval ${1+"$@"}
-    bootstrap_parse_options_result=$func_quote_for_eval_result
+    func_quote eval ${1+"$@"}
+    bootstrap_parse_options_result=$func_quote_result
 }
 func_add_hook func_parse_options bootstrap_parse_options
 
@@ -5279,8 +5328,8 @@ bootstrap_validate_options ()
         && func_fatal_help "too many arguments"
 
     # Pass back the (empty) list of unconsumed options.
-    func_quote_for_eval ${1+"$@"}
-    bootstrap_validate_options_result=$func_quote_for_eval_result
+    func_quote eval ${1+"$@"}
+    bootstrap_validate_options_result=$func_quote_result
 }
 func_add_hook func_validate_options bootstrap_validate_options
 
diff --git a/build-aux/ltmain.in b/build-aux/ltmain.in
index b4c6bcd..1cbe875 100644
--- a/build-aux/ltmain.in
+++ b/build-aux/ltmain.in
@@ -390,8 +390,8 @@ libtool_options_prep ()
 
     if $_G_rc_lt_options_prep; then
       # Pass back the list of options.
-      func_quote_for_eval ${1+"$@"}
-      libtool_options_prep_result=$func_quote_for_eval_result
+      func_quote eval ${1+"$@"}
+      libtool_options_prep_result=$func_quote_result
     fi
 
     $_G_rc_lt_options_prep
@@ -497,8 +497,8 @@ libtool_parse_options ()
 
     if $_G_rc_lt_parse_options; then
       # save modified positional parameters for caller
-      func_quote_for_eval ${1+"$@"}
-      libtool_parse_options_result=$func_quote_for_eval_result
+      func_quote eval ${1+"$@"}
+      libtool_parse_options_result=$func_quote_result
     fi
 
     $_G_rc_lt_parse_options
@@ -558,8 +558,8 @@ libtool_validate_options ()
     }
 
     # Pass back the unparsed argument list
-    func_quote_for_eval ${1+"$@"}
-    libtool_validate_options_result=$func_quote_for_eval_result
+    func_quote eval ${1+"$@"}
+    libtool_validate_options_result=$func_quote_result
 }
 func_add_hook func_validate_options libtool_validate_options
 
@@ -1525,8 +1525,8 @@ func_mode_compile ()
       esac
     done
 
-    func_quote_for_eval "$libobj"
-    test "X$libobj" != "X$func_quote_for_eval_result" \
+    func_quote_arg pretty "$libobj"
+    test "X$libobj" != "X$func_quote_arg_result" \
       && $ECHO "X$libobj" | $GREP '[]~#^*{};<>?"'"'"'	 &()|`$[]' \
       && func_warning "libobj name '$libobj' may not contain shell special characters."
     func_dirname_and_basename "$obj" "/" ""
@@ -1599,8 +1599,8 @@ compiler."
 
     func_to_tool_file "$srcfile" func_convert_file_msys_to_w32
     srcfile=$func_to_tool_file_result
-    func_quote_for_eval "$srcfile"
-    qsrcfile=$func_quote_for_eval_result
+    func_quote_arg pretty "$srcfile"
+    qsrcfile=$func_quote_arg_result
 
     # Only build a PIC object if we are building libtool libraries.
     if test yes = "$build_libtool_libs"; then
@@ -2203,8 +2203,8 @@ func_mode_install ()
        case $nonopt in *shtool*) :;; *) false;; esac
     then
       # Aesthetically quote it.
-      func_quote_for_eval "$nonopt"
-      install_prog="$func_quote_for_eval_result "
+      func_quote_arg pretty "$nonopt"
+      install_prog="$func_quote_arg_result "
       arg=$1
       shift
     else
@@ -2214,8 +2214,8 @@ func_mode_install ()
 
     # The real first argument should be the name of the installation program.
     # Aesthetically quote it.
-    func_quote_for_eval "$arg"
-    func_append install_prog "$func_quote_for_eval_result"
+    func_quote_arg pretty "$arg"
+    func_append install_prog "$func_quote_arg_result"
     install_shared_prog=$install_prog
     case " $install_prog " in
       *[\\\ /]cp\ *) install_cp=: ;;
@@ -2272,12 +2272,12 @@ func_mode_install ()
       esac
 
       # Aesthetically quote the argument.
-      func_quote_for_eval "$arg"
-      func_append install_prog " $func_quote_for_eval_result"
+      func_quote_arg pretty "$arg"
+      func_append install_prog " $func_quote_arg_result"
       if test -n "$arg2"; then
-	func_quote_for_eval "$arg2"
+	func_quote_arg pretty "$arg2"
       fi
-      func_append install_shared_prog " $func_quote_for_eval_result"
+      func_append install_shared_prog " $func_quote_arg_result"
     done
 
     test -z "$install_prog" && \
@@ -2288,8 +2288,8 @@ func_mode_install ()
 
     if test -n "$install_override_mode" && $no_mode; then
       if $install_cp; then :; else
-	func_quote_for_eval "$install_override_mode"
-	func_append install_shared_prog " -m $func_quote_for_eval_result"
+	func_quote_arg pretty "$install_override_mode"
+	func_append install_shared_prog " -m $func_quote_arg_result"
       fi
     fi
 
@@ -2585,8 +2585,8 @@ func_mode_install ()
 	        relink_command=`$ECHO "$relink_command" | $SED 's%@OUTPUT@%'"$outputname"'%g'`
 
 	        $opt_quiet || {
-	          func_quote_for_expand "$relink_command"
-		  eval "func_echo $func_quote_for_expand_result"
+	          func_quote_arg expand,pretty "$relink_command"
+		  eval "func_echo $func_quote_arg_result"
 	        }
 	        if eval "$relink_command"; then :
 	          else
@@ -3365,8 +3365,8 @@ else
   if test \"\$libtool_execute_magic\" != \"$magic\"; then
     file=\"\$0\""
 
-    func_quote "$ECHO"
-    qECHO=$func_quote_result
+    func_quote_arg pretty "$ECHO"
+    qECHO=$func_quote_arg_result
     $ECHO "\
 
 # A function that is used when there is no print builtin or printf.
@@ -3376,7 +3376,7 @@ func_fallback_echo ()
 \$1
 _LTECHO_EOF'
 }
-    ECHO=\"$qECHO\"
+    ECHO=$qECHO
   fi
 
 # Very basic option parsing. These options are (a) specific to
@@ -4719,9 +4719,9 @@ func_mode_link ()
     while test "$#" -gt 0; do
       arg=$1
       shift
-      func_quote_for_eval "$arg"
-      qarg=$func_quote_for_eval_unquoted_result
-      func_append libtool_args " $func_quote_for_eval_result"
+      func_quote_arg pretty,unquoted "$arg"
+      qarg=$func_quote_arg_unquoted_result
+      func_append libtool_args " $func_quote_arg_result"
 
       # If the previous option needs an argument, assign it.
       if test -n "$prev"; then
@@ -5319,9 +5319,9 @@ func_mode_link ()
 	save_ifs=$IFS; IFS=,
 	for flag in $args; do
 	  IFS=$save_ifs
-          func_quote_for_eval "$flag"
-	  func_append arg " $func_quote_for_eval_result"
-	  func_append compiler_flags " $func_quote_for_eval_result"
+          func_quote_arg pretty "$flag"
+	  func_append arg " $func_quote_arg_result"
+	  func_append compiler_flags " $func_quote_arg_result"
 	done
 	IFS=$save_ifs
 	func_stripname ' ' '' "$arg"
@@ -5335,10 +5335,10 @@ func_mode_link ()
 	save_ifs=$IFS; IFS=,
 	for flag in $args; do
 	  IFS=$save_ifs
-          func_quote_for_eval "$flag"
-	  func_append arg " $wl$func_quote_for_eval_result"
-	  func_append compiler_flags " $wl$func_quote_for_eval_result"
-	  func_append linker_flags " $func_quote_for_eval_result"
+          func_quote_arg pretty "$flag"
+	  func_append arg " $wl$func_quote_arg_result"
+	  func_append compiler_flags " $wl$func_quote_arg_result"
+	  func_append linker_flags " $func_quote_arg_result"
 	done
 	IFS=$save_ifs
 	func_stripname ' ' '' "$arg"
@@ -5362,8 +5362,8 @@ func_mode_link ()
 
       # -msg_* for osf cc
       -msg_*)
-	func_quote_for_eval "$arg"
-	arg=$func_quote_for_eval_result
+	func_quote_arg pretty "$arg"
+	arg=$func_quote_arg_result
 	;;
 
       # Flags to be passed through unchanged, with rationale:
@@ -5386,8 +5386,8 @@ func_mode_link ()
       -t[45]*|-txscale*|-p|-pg|--coverage|-fprofile-*|-F*|@*|-tp=*|--sysroot=*| \
       -O*|-g*|-flto*|-fwhopr*|-fuse-linker-plugin|-fstack-protector*|-stdlib=*| \
       -specs=*)
-        func_quote_for_eval "$arg"
-	arg=$func_quote_for_eval_result
+        func_quote_arg pretty "$arg"
+	arg=$func_quote_arg_result
         func_append compile_command " $arg"
         func_append finalize_command " $arg"
         func_append compiler_flags " $arg"
@@ -5408,15 +5408,15 @@ func_mode_link ()
 	  continue
         else
 	  # Otherwise treat like 'Some other compiler flag' below
-	  func_quote_for_eval "$arg"
-	  arg=$func_quote_for_eval_result
+	  func_quote_arg pretty "$arg"
+	  arg=$func_quote_arg_result
         fi
 	;;
 
       # Some other compiler flag.
       -* | +*)
-        func_quote_for_eval "$arg"
-	arg=$func_quote_for_eval_result
+        func_quote_arg pretty "$arg"
+	arg=$func_quote_arg_result
 	;;
 
       *.$objext)
@@ -5536,8 +5536,8 @@ func_mode_link ()
       *)
 	# Unknown arguments in both finalize_command and compile_command need
 	# to be aesthetically quoted because they are evaled later.
-	func_quote_for_eval "$arg"
-	arg=$func_quote_for_eval_result
+	func_quote_arg pretty "$arg"
+	arg=$func_quote_arg_result
 	;;
       esac # arg
 
@@ -8043,8 +8043,8 @@ EOF
 	    for cmd in $concat_cmds; do
 	      IFS=$save_ifs
 	      $opt_quiet || {
-		  func_quote_for_expand "$cmd"
-		  eval "func_echo $func_quote_for_expand_result"
+		  func_quote_arg expand,pretty "$cmd"
+		  eval "func_echo $func_quote_arg_result"
 	      }
 	      $opt_dry_run || eval "$cmd" || {
 		lt_exit=$?
@@ -8137,8 +8137,8 @@ EOF
 	  eval cmd=\"$cmd\"
 	  IFS=$save_ifs
 	  $opt_quiet || {
-	    func_quote_for_expand "$cmd"
-	    eval "func_echo $func_quote_for_expand_result"
+	    func_quote_arg expand,pretty "$cmd"
+	    eval "func_echo $func_quote_arg_result"
 	  }
 	  $opt_dry_run || eval "$cmd" || {
 	    lt_exit=$?
@@ -8612,12 +8612,12 @@ EOF
 	  elif eval var_value=\$$var; test -z "$var_value"; then
 	    relink_command="$var=; export $var; $relink_command"
 	  else
-	    func_quote_for_eval "$var_value"
-	    relink_command="$var=$func_quote_for_eval_result; export $var; $relink_command"
+	    func_quote_arg pretty "$var_value"
+	    relink_command="$var=$func_quote_arg_result; export $var; $relink_command"
 	  fi
 	done
-	func_quote "(cd `pwd`; $relink_command)"
-	relink_command=$func_quote_result
+	func_quote_arg pretty,unquoted "(cd `pwd`; $relink_command)"
+	relink_command=$func_quote_arg_unquoted_result
       fi
 
       # Only actually do things if not in dry run mode.
@@ -8857,14 +8857,14 @@ EOF
 	elif eval var_value=\$$var; test -z "$var_value"; then
 	  relink_command="$var=; export $var; $relink_command"
 	else
-	  func_quote_for_eval "$var_value"
-	  relink_command="$var=$func_quote_for_eval_result; export $var; $relink_command"
+	  func_quote_arg pretty,unquoted "$var_value"
+	  relink_command="$var=$func_quote_arg_unquoted_result; export $var; $relink_command"
 	fi
       done
       # Quote the link command for shipping.
       relink_command="(cd `pwd`; $SHELL \"$progpath\" $preserve_args --mode=relink $libtool_args @inst_prefix_dir@)"
-      func_quote "$relink_command"
-      relink_command=$func_quote_result
+      func_quote_arg pretty,unquoted "$relink_command"
+      relink_command=$func_quote_arg_unquoted_result
       if test yes = "$hardcode_automatic"; then
 	relink_command=
       fi
diff --git a/gl/build-aux/bootstrap.in b/gl/build-aux/bootstrap.in
index 6e686da..6da21d9 100755
--- a/gl/build-aux/bootstrap.in
+++ b/gl/build-aux/bootstrap.in
@@ -232,7 +232,7 @@ vc_ignore=
 . `echo "$0" |${SED-sed} 's|[^/]*$||'`"extract-trace"
 
 # Set a version string for *this* script.
-scriptversion=2015-01-20.17; # UTC
+scriptversion=2015-10-12.13; # UTC

 ## ------------------- ##
@@ -260,8 +260,8 @@ func_bootstrap ()
 
     # Save the current positional parameters to prevent them being
     # corrupted by calls to 'set' in 'func_init'.
-    func_quote_for_eval ${1+"$@"}
-    _G_saved_positional_parameters=$func_quote_for_eval_result
+    func_quote eval ${1+"$@"}
+    _G_saved_positional_parameters=$func_quote_result
 
     # Initialisation.
     func_init
@@ -2300,8 +2300,8 @@ func_show_eval ()
     _G_fail_exp=${2-':'}
 
     ${opt_silent-'false'} || {
-      func_quote_for_eval $_G_cmd
-      eval func_truncate_cmd $func_quote_for_eval_result
+      func_quote eval $_G_cmd
+      eval func_truncate_cmd $func_quote_result
       func_echo "running: $tc_bold$func_truncate_cmd_result$tc_reset"
     }
 
@@ -2688,8 +2688,8 @@ bootstrap_options_prep ()
     opt_skip_po=false
 
     # Pass back the list of options we consumed.
-    func_quote_for_eval ${1+"$@"}
-    bootstrap_options_prep_result=$func_quote_for_eval_result
+    func_quote eval ${1+"$@"}
+    bootstrap_options_prep_result=$func_quote_result
 }
 func_add_hook func_options_prep bootstrap_options_prep
 
@@ -2739,8 +2739,8 @@ bootstrap_parse_options ()
     done
 
     # save modified positional parameters for caller
-    func_quote_for_eval ${1+"$@"}
-    bootstrap_parse_options_result=$func_quote_for_eval_result
+    func_quote eval ${1+"$@"}
+    bootstrap_parse_options_result=$func_quote_result
 }
 func_add_hook func_parse_options bootstrap_parse_options
 
@@ -2758,8 +2758,8 @@ bootstrap_validate_options ()
         && func_fatal_help "too many arguments"
 
     # Pass back the (empty) list of unconsumed options.
-    func_quote_for_eval ${1+"$@"}
-    bootstrap_validate_options_result=$func_quote_for_eval_result
+    func_quote eval ${1+"$@"}
+    bootstrap_validate_options_result=$func_quote_result
 }
 func_add_hook func_validate_options bootstrap_validate_options
 
diff --git a/gl/build-aux/funclib.sh b/gl/build-aux/funclib.sh
index 47d8b95..2c22db1 100644
--- a/gl/build-aux/funclib.sh
+++ b/gl/build-aux/funclib.sh
@@ -1,5 +1,5 @@
 # Set a version string for this script.
-scriptversion=2015-10-04.22; # UTC
+scriptversion=2015-10-12.13; # UTC
 
 # General shell script boiler plate, and helper functions.
 # Written by Gary V. Vaughan, 2004
@@ -515,16 +515,16 @@ if test yes = "$_G_HAVE_PLUSEQ_OP"; then
   {
     $debug_cmd
 
-    func_quote_for_eval "$2"
-    eval "$1+=\\ \$func_quote_for_eval_result"
+    func_quote_arg pretty "$2"
+    eval "$1+=\\ \$func_quote_arg_result"
   }'
 else
   func_append_quoted ()
   {
     $debug_cmd
 
-    func_quote_for_eval "$2"
-    eval "$1=\$$1\\ \$func_quote_for_eval_result"
+    func_quote_arg pretty "$2"
+    eval "$1=\$$1\\ \$func_quote_arg_result"
   }
 fi
 
@@ -1026,135 +1026,184 @@ func_relative_path ()
 }

-# func_quote ARG
-# --------------
-# Aesthetically quote one ARG, store the result into $func_quote_result.  Note
-# that we keep attention to performance here (so far O(N) complexity as long as
-# func_append is O(1)).
-func_quote ()
+# func_quote_portable EVAL ARG
+# ----------------------------
+# Internal function to portably implement func_quote_arg.  Note that we still
+# keep attention to performance here so we as much as possible try to avoid
+# calling sed binary (so far O(N) complexity as long as func_append is O(1)).
+func_quote_portable ()
 {
     $debug_cmd
 
-    func_quote_result=$1
+    func_quote_portable_result=$2
 
-    case $func_quote_result in
-      *[\\\`\"\$]*)
-        case $func_quote_result in
-          *[\[\*\?]*)
-            func_quote_result=`$ECHO "$func_quote_result" | $SED "$sed_quote_subst"`
-            return 0
-            ;;
-        esac
+    # one-time-loop (easy break)
+    while true
+    do
+      if $1; then
+        func_quote_portable_result=`$ECHO "$2" | $SED \
+          -e "$sed_double_quote_subst" -e "$sed_double_backslash"`
+        break
+      fi
 
-        func_quote_old_IFS=$IFS
-        for _G_char in '\' '`' '"' '$'
-        do
-          # STATE($1) PREV($2) SEPARATOR($3)
-          set start "" ""
-          func_quote_result=dummy"$_G_char$func_quote_result$_G_char"dummy
-          IFS=$_G_char
-          for _G_part in $func_quote_result
+      # Quote for eval.
+      case $func_quote_portable_result in
+        *[\\\`\"\$]*)
+          case $func_quote_portable_result in
+            *[\[\*\?]*)
+              func_quote_portable_result=`$ECHO "$func_quote_portable_result" | $SED "$sed_quote_subst"`
+              break
+              ;;
+          esac
+
+          func_quote_portable_old_IFS=$IFS
+          for _G_char in '\' '`' '"' '$'
           do
-            case $1 in
-            quote)
-              func_append func_quote_result "$3$2"
-              set quote "$_G_part" "\\$_G_char"
-              ;;
-            start)
-              set first "" ""
-              func_quote_result=
-              ;;
-            first)
-              set quote "$_G_part" ""
-              ;;
-            esac
+            # STATE($1) PREV($2) SEPARATOR($3)
+            set start "" ""
+            func_quote_portable_result=dummy"$_G_char$func_quote_portable_result$_G_char"dummy
+            IFS=$_G_char
+            for _G_part in $func_quote_portable_result
+            do
+              case $1 in
+              quote)
+                func_append func_quote_portable_result "$3$2"
+                set quote "$_G_part" "\\$_G_char"
+                ;;
+              start)
+                set first "" ""
+                func_quote_portable_result=
+                ;;
+              first)
+                set quote "$_G_part" ""
+                ;;
+              esac
+            done
           done
-          IFS=$func_quote_old_IFS
-        done
+          IFS=$func_quote_portable_old_IFS
+          ;;
+        *) ;;
+      esac
+      break
+    done
+
+    func_quote_portable_unquoted_result=$func_quote_portable_result
+    case $func_quote_portable_result in
+      # double-quote args containing shell metacharacters to delay
+      # word splitting, command substitution and variable expansion
+      # for a subsequent eval.
+      # many bourne shells cannot handle close brackets correctly
+      # in scan sets, so we specify it separately.
+      *[\[\~\#\^\&\*\(\)\{\}\|\;\<\>\?\'\ \	]*|*]*|"")
+        func_quote_portable_result=\"$func_quote_portable_result\"
         ;;
-      *) ;;
     esac
 }

-# func_quote_for_eval ARG...
-# --------------------------
-# Aesthetically quote ARGs to be evaled later.
-# This function returns two values:
-#   i) func_quote_for_eval_result
-#      double-quoted, suitable for a subsequent eval
-#  ii) func_quote_for_eval_unquoted_result
+# func_quotefast_eval ARG
+# -----------------------
+# Quote one ARG (internal).  This is equivalent to 'func_quote_arg eval ARG',
+# but optimized for speed.  Result is stored in $func_quotefast_eval.
+if test xyes = `(x=; printf -v x %q yes; echo x"$x") 2>/dev/null`; then
+  func_quotefast_eval ()
+  {
+    printf -v func_quotefast_eval_result %q "$1"
+  }
+else
+  func_quotefast_eval ()
+  {
+    func_quote_portable false "$1"
+    func_quotefast_eval_result=$func_quote_portable_result
+  }
+fi
+
+
+# func_quote_arg MODEs ARG
+# ------------------------
+# Quote one ARG to be evaled later.  MODEs argument may contain zero ore more
+# specifiers listed below separated by ',' character.  This function returns two
+# values:
+#   i) func_quote_arg_result
+#      double-quoted (when needed), suitable for a subsequent eval
+#  ii) func_quote_arg_unquoted_result
 #      has all characters that are still active within double
-#      quotes backslashified.
-func_quote_for_eval ()
+#      quotes backslashified.  Available only if 'unquoted' is specified.
+#
+# Available modes:
+# ----------------
+# 'eval' (default)
+#       - escape shell special characters
+# 'expand'
+#       - the same as 'eval';  but do not quote variable references
+# 'pretty'
+#       - request aesthetic output, i.e. '"a b"' instead of 'a\ b'.  This might
+#         later used in func_quote to get output like: 'echo "a b"' instead of
+#         'echo a\ b'.  This is slower than default on some shells.
+# 'unquoted'
+#       - produce also $func_quote_arg_unquoted_result which does not contain
+#         wrapping double-quotes.
+#
+# Examples for 'func_quote_arg pretty,unquoted string':
+#
+#   string      | *_result              | *_unquoted_result
+#   ------------+-----------------------+-------------------
+#   "           | \"                    | \"
+#   a b         | "a b"                 | a b
+#   "a b"       | "\"a b\""             | \"a b\"
+#   *           | "*"                   | *
+#   z="${x-$y}" | "z=\"\${x-\$y}\""     | z=\"\${x-\$y}\"
+#
+# Examples for 'func_quote_arg pretty,unquoted,expand string':
+#
+#   string        |   *_result          |  *_unquoted_result
+#   --------------+---------------------+--------------------
+#   z="${x-$y}"   | "z=\"${x-$y}\""     | z=\"${x-$y}\"
+func_quote_arg ()
+{
+    _G_quote_expand=false
+    case ,$1, in
+      *,expand,*)
+        _G_quote_expand=:
+        ;;
+    esac
+
+    case ,$1, in
+      *,pretty,*|*,expand,*|*,unquoted,*)
+        func_quote_portable $_G_quote_expand "$2"
+        func_quote_arg_result=$func_quote_portable_result
+        func_quote_arg_unquoted_result=$func_quote_portable_unquoted_result
+        ;;
+      *)
+        # Faster quote-for-eval for some shells.
+        func_quotefast_eval "$2"
+        func_quote_arg_result=$func_quotefast_eval_result
+        ;;
+    esac
+}
+
+
+# func_quote MODEs ARGs...
+# ------------------------
+# Quote all ARGs to be evaled later and join them into single command.  See
+# func_quote_arg's description for more info.
+func_quote ()
 {
     $debug_cmd
-
-    func_quote_for_eval_unquoted_result=
-    func_quote_for_eval_result=
+    _G_func_quote_mode=$1 ; shift
+    func_quote_result=
     while test 0 -lt $#; do
-      func_quote "$1"
-      _G_unquoted_arg=$func_quote_result
-      if test -n "$func_quote_for_eval_unquoted_result"; then
-	func_append func_quote_for_eval_unquoted_result " $_G_unquoted_arg"
+      func_quote_arg "$_G_func_quote_mode" "$1"
+      if test -n "$func_quote_result"; then
+        func_append func_quote_result " $func_quote_arg_result"
       else
-        func_append func_quote_for_eval_unquoted_result "$_G_unquoted_arg"
-      fi
-
-      case $_G_unquoted_arg in
-        # Double-quote args containing shell metacharacters to delay
-        # word splitting, command substitution and variable expansion
-        # for a subsequent eval.
-        # Many Bourne shells cannot handle close brackets correctly
-        # in scan sets, so we specify it separately.
-        *[\[\~\#\^\&\*\(\)\{\}\|\;\<\>\?\'\ \	]*|*]*|"")
-          _G_quoted_arg=\"$_G_unquoted_arg\"
-          ;;
-        *)
-          _G_quoted_arg=$_G_unquoted_arg
-	  ;;
-      esac
-
-      if test -n "$func_quote_for_eval_result"; then
-	func_append func_quote_for_eval_result " $_G_quoted_arg"
-      else
-        func_append func_quote_for_eval_result "$_G_quoted_arg"
+        func_append func_quote_result "$func_quote_arg_result"
       fi
       shift
     done
 }

-# func_quote_for_expand ARG
-# -------------------------
-# Aesthetically quote ARG to be evaled later; same as above,
-# but do not quote variable references.
-func_quote_for_expand ()
-{
-    $debug_cmd
-
-    case $1 in
-      *[\\\`\"]*)
-	_G_arg=`$ECHO "$1" | $SED \
-	    -e "$sed_double_quote_subst" -e "$sed_double_backslash"` ;;
-      *)
-        _G_arg=$1 ;;
-    esac
-
-    case $_G_arg in
-      # Double-quote args containing shell metacharacters to delay
-      # word splitting and command substitution for a subsequent eval.
-      # Many Bourne shells cannot handle close brackets correctly
-      # in scan sets, so we specify it separately.
-      *[\[\~\#\^\&\*\(\)\{\}\|\;\<\>\?\'\ \	]*|*]*|"")
-        _G_arg=\"$_G_arg\"
-        ;;
-    esac
-
-    func_quote_for_expand_result=$_G_arg
-}
-
-
 # func_stripname PREFIX SUFFIX NAME
 # ---------------------------------
 # strip PREFIX and SUFFIX from NAME, and store in func_stripname_result.
@@ -1197,8 +1246,8 @@ func_show_eval ()
     _G_cmd=$1
     _G_fail_exp=${2-':'}
 
-    func_quote_for_expand "$_G_cmd"
-    eval "func_notquiet $func_quote_for_expand_result"
+    func_quote_arg pretty,expand "$_G_cmd"
+    eval "func_notquiet $func_quote_arg_result"
 
     $opt_dry_run || {
       eval "$_G_cmd"
@@ -1223,8 +1272,8 @@ func_show_eval_locale ()
     _G_fail_exp=${2-':'}
 
     $opt_quiet || {
-      func_quote_for_expand "$_G_cmd"
-      eval "func_echo $func_quote_for_expand_result"
+      func_quote_arg expand,pretty "$_G_cmd"
+      eval "func_echo $func_quote_arg_result"
     }
 
     $opt_dry_run || {
diff --git a/gl/build-aux/options-parser b/gl/build-aux/options-parser
index 4c7e9cb..c2bf9b4 100644
--- a/gl/build-aux/options-parser
+++ b/gl/build-aux/options-parser
@@ -1,7 +1,7 @@
 #! /bin/sh
 
 # Set a version string for this script.
-scriptversion=2015-10-07.11; # UTC
+scriptversion=2015-10-12.13; # UTC
 
 # A portable, pluggable option parser for Bourne shell.
 # Written by Gary V. Vaughan, 2010
@@ -211,8 +211,8 @@ func_run_hooks ()
 #    '
 #        # No change in '$@' (ignored completely by this hook).  There is
 #        # no need to do the equivalent (but slower) action:
-#        # func_quote_for_eval ${1+"$@"}
-#        # my_options_prep_result=$func_quote_for_eval_result
+#        # func_quote eval ${1+"$@"}
+#        # my_options_prep_result=$func_quote_result
 #        false
 #    }
 #    func_add_hook func_options_prep my_options_prep
@@ -248,8 +248,8 @@ func_run_hooks ()
 #        done
 #
 #        if $args_changed; then
-#          func_quote_for_eval ${1+"$@"}
-#          my_silent_option_result=$func_quote_for_eval_result
+#          func_quote eval ${1+"$@"}
+#          my_silent_option_result=$func_quote_result
 #        fi
 #
 #        $args_changed
@@ -316,8 +316,8 @@ func_options ()
     if $_G_rc_options; then
       func_options_result=$_G_res_var
     else
-      func_quote_for_eval ${1+"$@"}
-      func_options_result=$func_quote_for_eval_result
+      func_quote eval ${1+"$@"}
+      func_options_result=$func_quote_result
     fi
 
     $_G_rc_options
@@ -460,8 +460,8 @@ func_parse_options ()
 
     if $_G_rc_parse_options; then
       # save modified positional parameters for caller
-      func_quote_for_eval ${1+"$@"}
-      func_parse_options_result=$func_quote_for_eval_result
+      func_quote eval ${1+"$@"}
+      func_parse_options_result=$func_quote_result
     fi
 
     $_G_rc_parse_options
diff --git a/gl/doc/bootstrap.texi b/gl/doc/bootstrap.texi
index 2f7b382..b28bd71 100755
--- a/gl/doc/bootstrap.texi
+++ b/gl/doc/bootstrap.texi
@@ -390,8 +390,8 @@ my_silent_option ()
     esac
 
     # return modified option list
-    func_quote_for_eval $@{1+"$@@"@}
-    func_run_hooks_result=$func_quote_for_eval_result
+    func_quote eval $@{1+"$@@"@}
+    func_run_hooks_result=$func_quote_result
 @}
 func_add_hook func_parse_options my_silent_option
 @end smallexample
diff --git a/libtoolize.in b/libtoolize.in
index 798bd0a..3fe61ce 100644
--- a/libtoolize.in
+++ b/libtoolize.in
@@ -151,11 +151,11 @@ libtoolize_environment_options ()
 
     # Pass back the updated list of options.
     if test -n "$envopts"; then
-      func_quote_for_eval "$envopts" ${1+"$@"}
+      func_quote eval "$envopts" ${1+"$@"}
     else
-      func_quote_for_eval ${1+"$@"}
+      func_quote eval ${1+"$@"}
     fi
-    libtoolize_environment_options_result=$func_quote_for_eval_result
+    libtoolize_environment_options_result=$func_quote_result
 }
 func_add_hook func_options_prep libtoolize_environment_options
 
@@ -181,8 +181,8 @@ libtoolize_options_prep ()
     ltdl_mode=
 
     # Pass back the list of options.
-    func_quote_for_eval ${1+"$@"}
-    libtoolize_options_prep_result=$func_quote_for_eval_result
+    func_quote eval ${1+"$@"}
+    libtoolize_options_prep_result=$func_quote_result
 }
 func_add_hook func_options_prep libtoolize_options_prep
 
@@ -252,8 +252,8 @@ libtoolize_parse_options ()
     done
 
     # save modified positional parameters for caller
-    func_quote_for_eval ${1+"$@"}
-    libtoolize_parse_options_result=$func_quote_for_eval_result
+    func_quote eval ${1+"$@"}
+    libtoolize_parse_options_result=$func_quote_result
 }
 func_add_hook func_parse_options libtoolize_parse_options
 
@@ -286,8 +286,8 @@ libtoolize_validate_options ()
       func_fatal_help "unknown additional arguments: '${1+$@}'"
 
     # Pass back the empty argument list
-    func_quote_for_eval ${1+"$@"}
-    libtoolize_validate_options_result=$func_quote_for_eval_result
+    func_quote eval ${1+"$@"}
+    libtoolize_validate_options_result=$func_quote_result
 }
 func_add_hook func_validate_options libtoolize_validate_options
 
-- 
2.5.0