build: support warnings on RHEL 5

Without this, a configure built by autoconf 2.59 was broken when
trying to detect which compiler warning flags were supported.

* .gnulib: Update to latest, for warnings.m4 fix.
* bootstrap.conf: Add fclose explicitly, to match recent gnulib
implicit dependency changes.
* src/qemu/qemu_conf.c (includes): Drop unused include.
* src/uml/uml_conf.c (include): Likewise.
Reported by Daniel P. Berrange.

bootstrap.conf

@@ -36,6 +36,7 @@ configmake
 count-one-bits
 crypto/md5
 dirname-lgpl
+fclose
 fcntl-h
 ffs
 fnmatch