Original commit message from CVS:
2004-01-28  Julien MOUTTE  <julien@moutte.net>

* sys/ximage/ximagesink.c: (gst_ximagesink_handle_xerror),
(gst_ximagesink_check_xshm_calls), (gst_ximagesink_ximage_destroy),
(gst_ximagesink_xcontext_get), (gst_ximagesink_class_init):
* sys/xvimage/xvimagesink.c: (gst_xvimagesink_handle_xerror),
(gst_xvimagesink_check_xshm_calls),
(gst_xvimagesink_xvimage_destroy), (gst_xvimagesink_xcontext_get): Our
X plugins are now able to detect that XShm calls will fail even if the
server claims that it has XShm support (remote displays most of the
time). We then log the error as a GST_DEBUG and set use_shm to FALSE
so that we use non XShm functions. This feature is almost useless for
xvimagesink as Xv is not supported on remote displays anyway, but
it might happen than even on the local display XShm calls fail.