The HACKING file lists some files not to edit that are part of gnulib.
The contents for this list has been expanded to include various files,
including some m4 files.
* HACKING: Added other symbolic links to list of files not to edit.
COPYING
INSTALL
doc/
+ + gendocs_template
+ + gendocs_template_min
+ fdl.texi
libltdl/
+ COPYING.LIB
+ mdate-sh
+ missing
+ texinfo.tex
+ m4/
+ + 00gnulib.m4
+ + gnulib-cache.m4
+ + gnulib-common.m4
+ + gnu-comp.m4
+ + gnulib-tool.m4
+ + ltversion.m4
+ + zzgnulib.m4
+ GNUmakefile
+ maint.mk
+
The ones that are important for a release can be updated by ensuring
gnulib is up-to-date, and running 'bootstrap' to recheck the links are
correct.