* bootstrap (insert_sorted_if_absent): Replace all uses with...
(insert_vc_ignore): ... this new function, which prepends `/' to all
.gitignore entries before passing them to insert_sorted_if_absent.
* bootstrap.conf (vc_ignore): Set to '.cvsignore .gitignore' so that
.cvsignore files are maintained even though Bison developers run
bootstrap while using Git.
* .cvsignore (*.patch *.log log patches applied): Remove, apparently
unneeded by Bison.
(gnulib): Add.
* .gitignore (/*.patch *.log log patches applied): Remove, broken and
unneeded. Reported by Eric Blake.
* lib/.gitignore (/*~): Add.
* po/.cvsignore, runtime-po/.cvsignore: Sync with .gitignore.
* examples/calc++/.gitignore (/calc++.exe): Add. Reported by Eric
Blake.
* src/.gitignore (/bison.exe): Add. Reported by Eric Blake.
Reported by Eric Blake at
<http://lists.gnu.org/archive/html/bug-bison/2008-07/msg00000.html>.
* bootstrap.conf (gnulib_modules): Add unsetenv.
* lib/.gitignore, lib/.cvsignore (/unsetenv.c): Add.
* m4/.gitignore, m4/.cvsignore (/environ.m4): Add.
(/setenv.m4): Add.
* src/output.c (output_skeleton): For the m4 invocation, pass -dV as
the first argument because it may become position-dependent, and unset
POSIXLY_CORRECT so Bison's skeletons have access to GNU M4 extensions.
Add comments explaining these issues in more detail.