Add import_function method to test.test_support, and modify a number of
tests that expect to be skipped if imports fail or functions don't
exist to use import_function and import_module.  The ultimate goal is
to change regrtest to not skip automatically on ImportError.  Checking
in now to make sure the buldbots don't show any errors on platforms
I can't direct test on.
diff --git a/Lib/test/test_applesingle.py b/Lib/test/test_applesingle.py
index e915028..5a8201c 100644
--- a/Lib/test/test_applesingle.py
+++ b/Lib/test/test_applesingle.py
@@ -1,13 +1,15 @@
 # Copyright (C) 2003 Python Software Foundation
 
 import unittest
-import macostools
-import Carbon.File
-import MacOS
 import os
 from test import test_support
 import struct
+
+MacOS = test_support.import_module('MacOS')
+# The following should exist if MacOS does.
+import macostools
 import applesingle
+import Carbon.File
 
 AS_MAGIC=0x00051600
 AS_VERSION=0x00020000