Fix warnings on 64-bit platforms about casts from pointers to ints.
Two of these were real bugs.
diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index c090e9b..92adb49 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -3883,7 +3883,8 @@
 				PyErr_Format(PyExc_ValueError,
 				  "unsupported format character '%c' (0x%x) "
 				  "at index %i",
-				  c, c, fmt - 1 - PyString_AsString(format));
+				  c, c,
+				  (int)(fmt - 1 - PyString_AsString(format)));
 				goto error;
 			}
 			if (sign) {