--- a/mercurial/util.h	Sat Oct 08 19:02:44 2016 +0200
+++ b/mercurial/util.h	Sat Oct 08 19:16:50 2016 +0200
@@ -13,6 +13,9 @@
 #if PY_MAJOR_VERSION >= 3
 
 #define IS_PY3K
+/* The mapping of Python types is meant to be temporary to get Python
+ * 3 to compile. We should remove this once Python 3 support is fully
+ * supported and proper types are used in the extensions themselves. */
 #define PyInt_Type PyLong_Type
 #define PyInt_FromLong PyLong_FromLong
 #define PyInt_AsLong PyLong_AsLong