p4raw-id: //depot/perl@3695
SvREFCNT_inc() was called too few times, or that the SV was mortalized
when it shouldn't have been, or that memory has been corrupted.
+=item Attempt to join self
+
+(F) You tried to join a thread from within itself, which is an
+impossible task. You may be joining the wrong thread, or you may
+need to move the join() to some other thread.
+
=item Attempt to pack pointer to temporary value
(W) You tried to pass a temporary value (like the result of a