Try to fix the test on 64-bit platforms.

Lib/ctypes/test/test_memfunctions.py

@@ -8,11 +8,10 @@ class MemFunctionsTest(unittest.TestCase):
         # convention (which acquires the GIL and checks the Python
         # error flag).  Provoke an error and catch it; see also issue
         # #3554: <http://bugs.python.org/issue3554>
-        if hasattr(sys, "maxsize"):
-            self.assertRaises((OverflowError, MemoryError),
-                              lambda: wstring_at(u"foo", sys.maxsize))
-            self.assertRaises((OverflowError, MemoryError),
-                              lambda: string_at("foo", sys.maxsize))
+        self.assertRaises((OverflowError, MemoryError, SystemError),
+                          lambda: wstring_at(u"foo", sys.maxint - 1))
+        self.assertRaises((OverflowError, MemoryError, SystemError),
+                          lambda: string_at("foo", sys.maxint - 1))
 
     def test_memmove(self):
         # large buffers apparently increase the chance that the memory