Use Py_intptr_t to store the difference between two pointers, instead of int

Fix a compiler warning on Windows 64-bit

Objects/descrobject.c

@@ -1009,7 +1009,7 @@ wrapper_dealloc(wrapperobject *wp)
 static PyObject *
 wrapper_richcompare(PyObject *a, PyObject *b, int op)
 {
-    int result;
+    Py_intptr_t result;
     PyObject *v;
     PyWrapperDescrObject *a_descr, *b_descr;