Upgrade pyexpat to expat 2.0.0 (http://python.org/sf/1462338).
diff --git a/Modules/expat/xmltok_ns.c b/Modules/expat/xmltok_ns.c
index 5610eb9..d2f8938 100644
--- a/Modules/expat/xmltok_ns.c
+++ b/Modules/expat/xmltok_ns.c
@@ -19,7 +19,7 @@
 #endif
 }
 
-static const ENCODING *NS(encodings)[] = {
+static const ENCODING * const NS(encodings)[] = {
   &ns(latin1_encoding).enc,
   &ns(ascii_encoding).enc,
   &ns(utf8_encoding).enc,