Make sure the split up -devel package require avahi-devel
    
    This adds back the dependency on the base -devel that was dropped in
    commit b09f78ff7fd369ad57fca60db5676b2ac3d18ab9.
    
    Most of the existing packages just have deps on e.g. avahi-glib-devel
    and expect to have avahi-devel pulled in as well, failing to build
    otherwise.