Gtk/DFB requires pango cairo

["Mike Emmel" <mike emmel gmail com>]

http://bugzilla.gnome.org/show_bug.cgi?id=476823

This happens quite a bit gdk directfb requires the pango/cairo backend.

First I don't know the best way to check pango for a particular backend.

Next considering cairo is now required for gtk I'd suggest that the pango build
have cairo on by default and require that you have to disable it on purpose.