Original commit message from CVS:
* sys/ximage/ximagesink.c: (gst_ximagesink_sink_link),
(gst_ximagesink_set_xwindow_id), (gst_ximagesink_init):
* sys/ximage/ximagesink.h:
* sys/xvimage/xvimagesink.c: (gst_xvimagesink_sink_link),
(gst_xvimagesink_set_xwindow_id), (gst_xvimagesink_init):
* sys/xvimage/xvimagesink.h:
Actually only create a new toplevel window if we're not gonna
embed it right after.