GitLab

* admin/merge-gnulib: rm m4/gnulib-tool.m4 too.
(GNULIB_MODULES): Remove unsetenv, as it is not needed and
the --avoid=unsetenv option avoided most of it anyway.
* lib/unsetenv.c, m4/gnulib-tool.m4, m4/setenv.m4: Remove.
* lib/gnulib.mk: Regenerate.