Issue #9586: Merge.

diff --cc Misc/NEWS
index ccbf416e3a4e2cbc3b3914bf24e6cc04f93bb274,efd4343af6bc4cdcf5ef5d327657387bf819f969..726777ec0a8122dcf124a7b5edb7f9d8f9396a70
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -200,10 -124,9 +200,12 @@@ Core and Builtin
  Library
  -------
  
 -- Issue 10527: make multiprocessing use poll() instead of select() if available.
+ - Issue #9586: Redefine SEM_FAILED on MacOSX to keep compiler happy.
+ 
 +- Issue #16787: Increase asyncore and asynchat default output buffers size, to
 +  decrease CPU usage and increase throughput.
 +
 +- Issue #10527: make multiprocessing use poll() instead of select() if available.
  
  - Issue #16688: Fix backreferences did make case-insensitive regex fail on
    non-ASCII strings. Patch by Matthew Barnett.

diff --cc Modules/_multiprocessing/semaphore.c
Simple merge