GDK clean-up and _gdk_windowing_exit

[Iulian Iliescu <iliescu iulian gmail com>]

I'm using GTK 2.12.12 with DirectFB and when gtk terminates DirectFB 
doesn't get released.
I observed that there is a function _gdk_windowing_exit() which should 
do the job, but this is never called.

Please explain me how can i do the clean-up?

Iulian