Ensure that distutils.tests.test_util will pass in 64-bit builds.

Fixes #7591
diff --git a/Lib/distutils/tests/test_util.py b/Lib/distutils/tests/test_util.py
index dcc1a20..0c732f8 100644
--- a/Lib/distutils/tests/test_util.py
+++ b/Lib/distutils/tests/test_util.py
@@ -96,7 +96,12 @@
         get_config_vars()['CFLAGS'] = ('-fno-strict-aliasing -DNDEBUG -g '
                                        '-fwrapv -O3 -Wall -Wstrict-prototypes')
 
-        self.assertEquals(get_platform(), 'macosx-10.3-i386')
+        cursize = sys.maxsize
+        sys.maxsize = (2 ** 31)-1
+        try:
+            self.assertEquals(get_platform(), 'macosx-10.3-i386')
+        finally:
+            sys.maxsize = cursize
 
         # macbook with fat binaries (fat, universal or fat64)
         os.environ['MACOSX_DEPLOYMENT_TARGET'] = '10.4'