Fix integer negation and absolute value to not rely
on undefined behaviour of the C compiler anymore.
diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
index ca7a8f3..f3bdbe2 100644
--- a/Lib/test/test_builtin.py
+++ b/Lib/test/test_builtin.py
@@ -116,6 +116,7 @@
         self.assertEqual(abs(0), 0)
         self.assertEqual(abs(1234), 1234)
         self.assertEqual(abs(-1234), 1234)
+        self.assertTrue(abs(-sys.maxint-1) > 0)
         # float
         self.assertEqual(abs(0.0), 0.0)
         self.assertEqual(abs(3.14), 3.14)