Skip 2038 bug test on 32 bit systems

This should fix bug #73.

Author: jim-easterbrook

tests/test_value.py

@@ -441,6 +441,8 @@ def test_DateValue(self):
         with self.subTest(date=date):
             self.do_test_DateValue(date)
         if exiv2.testVersion(0, 28, 4):
+            if sys.maxsize <= 2**32:
+                self.skipTest("Can't test 2038 bug on 32 bit system")
             date = datetime.date(2039, 1, 1)
             with self.subTest(date=date):
                 self.do_test_DateValue(date)