cext: fix compiler error in revlog.c on Windows with py2

Visual Studio 2008 doesn't have <stdint.h>, and we worked around it before with
this header.

Differential Revision: https://phab.mercurial-scm.org/D9804

mercurial/cext/revlog.c

@@ -13,10 +13,10 b''
 #include <ctype.h>
 #include <limits.h>
 #include <stddef.h>
-#include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 
+#include "compat.h"
 #include "bitmanipulation.h"
 #include "charencode.h"
 #include "revlog.h"