Currently, gnome-vfs simply enables/disables howl support based on finding the howl pkgconfig file. The to-come patch adds a --{en,dis}able-howl option to configure and behaves accordingly. I've tested this quite a bit, but am mostly unfamiliar with the gnome-foo, so this should prolly get some good testing before going in.
Created attachment 40128 [details] The ebuild Note: This is for 2.8.1 that was just released today.
Created attachment 40129 [details, diff] The patch. The patch for ${FILESDIR}
added gnome-vfs 2.8.1 with a modified patch enabled, thanks