Jonas Ådahl d188949101 backends/x11: Make the X11 backend derivable
Make the X11 backend derivable so that we can base a nested test backend
on it.

https://bugzilla.gnome.org/show_bug.cgi?id=777732
2017-01-25 16:28:53 +08:00
..
2016-07-20 14:23:48 +08:00