[Libvir] build problems on RHEL5, at least some are now fixed

Daniel Berrange noticed some build problems on RHEL5. Some were due to my not adding two .m4 files in yesterday's gnulib update. [excuse time ;-) Normally (in other projects), the gnulib-update process is automatic, since the imported files are not version-controlled, but for libvirt I have to identify new files pulled in by a gnulib update, and obviously didn't complete that step. Identifying and adding added files is not hard. Just have to remember to do it before committing anything. Actually, the trick is (as usual) to *automate* the process, so we don't have to depend on my memory. This is now on my list. Anyhow, I've committed the change.