sys/: Use flow_lock much more to protect every access to xwindow.

sys/: Use flow_lock much more to protect every access to xwindow.

Original commit message from CVS:
2007-01-07  Julien MOUTTE  <julien@moutte.net>

* sys/ximage/ximagesink.c: (gst_ximage_buffer_finalize),
(gst_ximagesink_handle_xerror), (gst_ximagesink_ximage_new),
(gst_ximagesink_ximage_destroy), (gst_ximagesink_ximage_put),
(gst_ximagesink_handle_xevents), (gst_ximagesink_setcaps),
(gst_ximagesink_change_state), (gst_ximagesink_set_xwindow_id),
(gst_ximagesink_expose), (gst_ximagesink_set_event_handling):
* sys/xvimage/xvimagesink.c: (gst_xvimage_buffer_destroy),
(gst_xvimage_buffer_finalize), (gst_xvimagesink_handle_xerror),
(gst_xvimagesink_xvimage_new), (gst_xvimagesink_xvimage_put),
(gst_xvimagesink_handle_xevents), (gst_xvimagesink_setcaps),
(gst_xvimagesink_change_state),
(gst_xvimagesink_set_xwindow_id),
(gst_xvimagesink_expose), (gst_xvimagesink_set_event_handling):
Use flow_lock much more to protect every access to xwindow.
Try to catch erros while creating images in case some drivers
are
just generating an XError when the requested image is too big.
Should fix : #354698, #384008, #384060.
* tests/icles/stress-xoverlay.c: (cycle_window),
(create_window):
Implement some stress testing of setting window xid.