Build fixes for the SDL flavour.
* clutter/sdl/clutter-backend-sdl.c: Remove an unused function.
* clutter/sdl/clutter-event-sdl.c:
(clutter_event_dispatch): Properly cast the stage pointer.
* clutter/sdl/clutter-stage-sdl.c:
(clutter_stage_window_iface_init): Remove the draw_to_pixbuf()
stub and assignment.