Normalize paths before writing them to a zipfile.
diff --git a/Lib/distutils/archive_util.py b/Lib/distutils/archive_util.py
index 050ea41..218450a 100644
--- a/Lib/distutils/archive_util.py
+++ b/Lib/distutils/archive_util.py
@@ -93,7 +93,7 @@
 
         def visit (z, dirname, names):
             for name in names:
-                path = os.path.join (dirname, name)
+                path = os.path.normpath(os.path.join(dirname, name))
                 if os.path.isfile (path):
                     z.write (path, path)