On 4/26/21 3:29 AM, David L. Craig wrote:

>> configure.ac:55: warning: The macro `AC_PROG_CC_STDC' is obsolete.

I reproduced these warnings; they come from Autoconf 2.71. You can 
ignore them, or you can update to the latest coreutils on Savannah, 
where I installed some patches (attached) to silence these.

>> doc/local.mk:19: installing 'build-aux/mdate-sh'
>> Makefile.am:213:   'doc/local.mk' included from here
>> doc/local.mk:19: error: required file 'build-aux/texinfo.tex' not found
>> Makefile.am:213:   'doc/local.mk' included from here

I don't observe this problem. gnulib-tool sets up a symlink that works:

$ ls -l build-aux/texinfo.tex gnulib/build-aux/texinfo.tex
lrwxrwxrwx 1 eggert eggert     31 Apr 26 23:59 build-aux/texinfo.tex -> 
../gnulib/build-aux/texinfo.tex
-rw-rw-r-- 1 eggert eggert 379274 Apr 26 23:56 gnulib/build-aux/texinfo.tex

If you still observe a problem with a fresh build from scratch, please 
investigate why gnulib-tool isn't setting up that link for you