cext: match format string for 32bit long platforms

Differential Revision: https://phab.mercurial-scm.org/D9546

mercurial/cext/revlog.c

@@ -370,7 +370,7 b' static int node_check(PyObject *obj, cha'
 
 static PyObject *index_append(indexObject *self, PyObject *obj)
 {
-	unsigned long offset_flags;
+	uint64_t offset_flags;
 	int rev, comp_len, uncomp_len, base_rev, link_rev, parent_1, parent_2;
 	Py_ssize_t c_node_id_len;
 	const char *c_node_id;