diff -r 0f4ac3b6dee4 -r a22339d389d4 mercurial/cext/charencode.h
--- a/mercurial/cext/charencode.h	Sun May 21 14:23:22 2017 +0900
+++ b/mercurial/cext/charencode.h	Mon Jul 31 22:58:06 2017 +0900
@@ -18,7 +18,7 @@
 	NORMCASE_OTHER = 0
 };
 
-PyObject *unhexlify(const char *str, int len);
+PyObject *unhexlify(const char *str, Py_ssize_t len);
 PyObject *asciilower(PyObject *self, PyObject *args);
 PyObject *asciiupper(PyObject *self, PyObject *args);
 PyObject *make_file_foldmap(PyObject *self, PyObject *args);