[patch] Lockup on wait on exited child with exited child

[Roland McGrath]

I think that drops it early (while still waiting for a report from the
parent) in case of a normal parent that just happens to be almost finished
exiting.  Unless I'm missing something, this extra droptcb should only be
required in the case of a zombie group leader that has already reported
and been short-circuited at the top of droptcb.  So I think it want the
same test used at the top of detach.


Thanks,
Roland