Original commit message from CVS: * sys/ximage/ximagesink.c: (gst_ximagesink_get_type): * sys/xvimage/xvimagesink.c: (gst_xvimagesink_get_type): Explicitly create our custom buffer classes at a thread-safe location as well, since g_type_class_ref() doesn't seem to be entirely thread-safe either (#365501; also see #349410).