Backport of pthread fixes from 5.x to 6.0.

[John Baldwin]

I'd like to backport most of the thread fixes for libpthread from 6.0 to 
RELENG_5 before 5.4.  I've been testing this patch locally and just wanted to 
make sure backporting it was ok with the folks on this list.  Patch is at 
http://www.FreeBSD.org/~jhb/patches/pthread_5.patch

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org