This incorporates:
2020-01-18 Rename ~~gnulib.m4 to zzgnulib.m4
2020-01-18 Fix "m4_require: circular dependency of AC_LANG_COMPILER(C)"
2020-01-18 Ensure Automake does not drop ~~gnulib.m4
2020-01-18 Fix major regression from 2020-01-10
* m4/00gnulib.m4, m4/gnulib-common.m4: Copy from Gnulib.
* m4/gnulib-comp.m4: Regenerate.
* m4/zzgnulib.m4: New file, from Gnulib.

This incorporates:
2020-01-10 fix major regression from 2020-01-04
2020-01-05 tests: avoid GCC over-optimization
2020-01-04 fix AC_CHECK_DECL so it deactivates clang's built-ins
2020-01-03 getopt-posix: fix compilation failure in testdirs
2020-01-03 doc: mention the 64-bit inode number problem
2020-01-02 wchar: make the HP-UX workaround work on HP-UX 11.31
* build-aux/config.guess, build-aux/config.sub, lib/inttypes.in.h:
* lib/stdlib.in.h, lib/unistd.in.h, m4/00gnulib.m4, m4/largefile.m4:
* m4/unistd_h.m4: Copy from Gnulib
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.

Run "TZ=UTC0 admin/update-copyright $(git ls-files)".

Run 'TZ=UTC0 admin/update-copyright $(git ls-files)'.

This incorporates:
2018-01-01 maint: Run 'make update-copyright'
2017-12-29 Add cross-compilation results for GNU/Hurd.
2017-12-12 explicit_bzero: port to macOS + Clang 9.0.0

Run admin/update-copyright.

This mostly just updates copyright dates of gnulib files.
It also updates to the latest version of texinfo.tex.

2015-01-01 version-etc: new year

This incorporates:
2014-01-07 update from texinfo
2014-01-06 md5, sha1, sha256, sha512: support older autoconf