gst/: Right, two problems here: ghostpads don't take locks and glib _rec_mutex_lock_f...

gst/: Right, two problems here: ghostpads don't take locks and glib _rec_mutex_lock_full() with depth==0 still locks.

Original commit message from CVS:
* gst/base/gstbasesink.c: (gst_basesink_preroll_queue_empty),
(gst_basesink_handle_object), (gst_basesink_event),
(gst_basesink_do_sync), (gst_basesink_handle_event),
(gst_basesink_change_state):
* gst/gsttask.h:
Right, two problems here: ghostpads don't take locks and
glib _rec_mutex_lock_full() with depth==0 still locks.
Catch illegal locking and g_warn them.