Issue #9586: Redefine SEM_FAILED on MacOSX to keep compiler happy.
diff --git a/Misc/NEWS b/Misc/NEWS
index 9e04951..a7e2534 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -189,6 +189,8 @@
 Library
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+- Issue #9586: Redefine SEM_FAILED on MacOSX to keep compiler happy.
+
 - Issue 10527: make multiprocessing use poll() instead of select() if available.
 
 - Issue #16485: Fix file descriptor not being closed if file header patching