#4170: Fix segfault when pickling a defauldict object.

The 2.x dict.iteritems() returns an iterator,
whereas the 3.0 dict.items() returns a "view",
which is iterable, but not an iterator with its __next__ method.

Patch by Hirokazu Yamamoto.
diff --git a/Misc/NEWS b/Misc/NEWS
index 5b5a125..a557b52 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -15,6 +15,9 @@
 Core and Builtins
 -----------------
 
+- Issue #4170: Pickling a collections.defaultdict object would crash the
+  interpreter.
+
 - Issue #4146: Compilation on OpenBSD has been restored.
 
 - Issue #3574: compile() incorrectly handled source code encoded as Latin-1.