maint: update to latest gnulib

maint: update to latest gnulib

CVE-2013-0242 in glibc's regex() can cause a DoS in any daemon
that runs a regex search on user input while in a multibyte locale.
I'm not sure how hard it would be to trigger such a setup for
libvirtd, but rather than risk things, we can avoid the issue:
gnulib has worked around the problem, and by updating to the latest
gnulib, we can avoid the bug even on platforms where glibc has yet
to be patched.

* .gnulib: Update to latest, for various fixes, including regex.
* bootstrap: Resync from upstream.