Comment # 4 on bug 928384 from C�dric Bosdonnat

Getting such a patch upstream is pretty hard: people tend not to want it in.

Would it be an option to use an external dnsmasq? This can be easily achieved
by using the bridge forward mode in the libvirt network definition. This
requires you to create a bridge and run dnsmasq outside of libvirt, but OTOH
this gives you full power on the dnsmasq config.