build: update to latest gnulib

Gnulib has been busy, with 397 commits; it's easier to update now
even without any known libvirt issue to be fixed, rather than
having to analyze an even larger changeset later on.

* .gnulib: Update to latest, for lots of changes.
* bootstrap: Synchronize to upstream.

.gnulib @ 478c2dcc

-Subproject commit 5bf7fda437a10cc10cbd1be1bd06b374a581f0dd
+Subproject commit 478c2dcc839e5f4765e6417684ce414e2d4973a8

bootstrap

 #! /bin/sh
 # Print a version string.
-scriptversion=2011-05-16.16; # UTC
+scriptversion=2011-06-22.06; # UTC
 
 # Bootstrap this package from checked-out sources.
 
@@ -290,7 +290,7 @@ sort_patterns() {
     P
     x
     s/^\n//
-  }'
+  }' | sed '/^$/d'
 }
 
 # If $STR is not already on a line by itself in $FILE, insert it,