patch applied (ghc): Always check the result of pthread_mutex_lock() and pthread_mutex_unlock().

[Simon Marlow]

Sun Jan  4 11:24:43 PST 2009  Matthias Kilian <kili at outback.escape.de>
  * Always check the result of pthread_mutex_lock() and pthread_mutex_unlock().
  
  Don't check pthread_mutex_*lock() only on Linux and/or only if DEBUG
  is defined. The return values of those functions are well defined
  and should be supported on all operation systems with pthreads. The
  checks are cheap enough to do them even in the default build (without
  -DDEBUG).
  
  While here, recycle an unused macro ASSERT_LOCK_NOTHELD, and let
  the debugBelch part enabled with -DLOCK_DEBUG work independently
  of -DDEBUG.
  

    M ./includes/OSThreads.h -30 +10

View patch online:
http://darcs.haskell.org/ghc/_darcs/patches/20090104192443-6d641-96782e004fc28649e8c9716b3f2bdcddddba0a76.gz