Remove locking of individual message files in MH.pack().
[Backport of rev52776 from the trunk.]
diff --git a/Misc/NEWS b/Misc/NEWS
index 221acbb..8324a05 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -158,6 +158,10 @@
been physically written to disk after calling .flush() or
.close(). (Patch by David Watson.)
+- mailbox.py: Change MH.pack() to not lock individual message files; this
+ wasn't consistent with existing implementations of message packing, and
+ was buggy on some platforms.
+
- Bug #1576241: fix functools.wraps() to work on built-in functions.
- Patch #1574068: fix urllib/urllib2 to not insert line breaks when