Files from gnulib

[Eli Zaretskii]

Some of the new files added from gnulib use file names that are
invalid on 8+3 (aka MSDOS) filesystems.  These files are:

 c++defs.h -- the `+' character is not allowed in file names
 lib/stddef.in.h lib/time.in.h lib/unistd.in.h -- 2 dots are not allowed

In addition, several file names in the m4/ subdirectory clash after
8+3 truncation:

 gnulib-cache.m4  gnulib-common.m4  gnulib-comp.m4

This will cause problems when unpacking the emacs tarball on those
filesystems, something we managed to avoid until now.

Can these files be renamed, please?  I suggest cxxdefs.h for the first
and FOO.in for the FOO.in.h files.  For the files in m4/, how about
transposing the "gnulib" part with the rest, i.e. cache-gnulib.m4
etc.?

(I would remove the files myself, but I don't know what changes in the
gnulib imports will that require.)

TIA