Issue #874900: fix behaviour of threading module after a fork.

Reviewed by Gregory P. Smith.
diff --git a/Misc/NEWS b/Misc/NEWS
index ef860a4..cacbef4 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -90,6 +90,8 @@
 Library
 -------
 
+- Issue #874900: fix behaviour of threading module after a fork.
+
 - Issue #3535: zipfile couldn't read some zip files larger than 2GB.
 
 - Issue #3776: Deprecate the bsddb package for removal in 3.0.