Building sysutils/gnome-vfs with avahi breaks devel/libgnome

[David Brownlee <abs%absd.org@localhost>]

This is an interesting one...

I have avahi in PKG_DEFAULT_OPTIONS

Attempting to build devel/libgnome, which requires sysutils/gnome-vfs.

sysutils/gnome-vfs builds with avahi, but does not export this
information via its buildlink3.mk, so when devel/libgnome builds we
get:

libtool: link: gcc -O2 -pipe
-I/var/obj/pkg/devel/libgnome/work/.buildlink/include
-I/var/obj/pkg/devel/libgnome/work/.x11-buildlink/include [...]
ld: cannot find -lavahi-glib
ld: cannot find -lavahi-client
ld: cannot find -lavahi-common

any thoughts? should devel/libgnome just support an avahi option too?