Part of SF patch 101481:  on Windows, os.path.join("a:", "b") should yield
"a:b", not "a:/b".  Similar change was made to posixmodule.c earlier.
diff --git a/Lib/ntpath.py b/Lib/ntpath.py
index aa441bd..c68232b 100644
--- a/Lib/ntpath.py
+++ b/Lib/ntpath.py
@@ -41,7 +41,7 @@
     for b in p:
         if isabs(b):
             path = b
-        elif path == '' or path[-1:] in '/\\':
+        elif path == '' or path[-1:] in '/\\:':
             path = path + b
         else:
             path = path + os.sep + b