Convert the internal ctypes array type cache to a WeakValueDict so
that array types do not live longer than needed.
diff --git a/Misc/NEWS b/Misc/NEWS
index 0be1934..0a7d00c 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -364,6 +364,9 @@
 Library
 -------
 
+- Convert the internal ctypes array type cache to a WeakValueDict so
+  that array types do not live longer than needed.
+
 - Issue #1786: pdb should use its own stdin/stdout around an exec call
   and when creating a recursive instance.