diff --git a/mercurial/parsers.c b/mercurial/parsers.c
--- a/mercurial/parsers.c
+++ b/mercurial/parsers.c
@@ -244,9 +244,9 @@ static PyObject *nullentry;
 static long inline_scan(indexObject *self, const char **offsets);
 
 #if LONG_MAX == 0x7fffffffL
-static const char *tuple_format = "Kiiiiiis#";
+static char *tuple_format = "Kiiiiiis#";
 #else
-static const char *tuple_format = "kiiiiiis#";
+static char *tuple_format = "kiiiiiis#";
 #endif
 
 /* RevlogNG format (all in big endian, data may be inlined):
diff --git a/mercurial/util.h b/mercurial/util.h
--- a/mercurial/util.h
+++ b/mercurial/util.h
@@ -107,6 +107,9 @@
    Note: msvc (8 or earlier) does not have ssize_t, so we use Py_ssize_t.
 */
 typedef int Py_ssize_t;
+typedef Py_ssize_t (*lenfunc)(PyObject *);
+typedef PyObject *(*ssizeargfunc)(PyObject *, Py_ssize_t);
+
 #if !defined(PY_SSIZE_T_MIN)
 #define PY_SSIZE_T_MAX INT_MAX
 #define PY_SSIZE_T_MIN INT_MIN