Use os.rmdir() for symlinks on windows.

dart/tools/make_links.py

 #!/usr/bin/env python
 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 
 '''Tool for creating symlinks from SOURCES to TARGET.
 
 For each SOURCE in SOURCES create a link from SOURCE to TARGET.  If a
 SOURCE ends with .../lib, the lib suffix is ignored when determining
@@ skipping 49 matching lines @@
 
 
 def main(argv):
   (options, args) = get_options()
   target = os.path.relpath(args[0])
   if os.path.exists(target):
     # If the packages directory already exists, delete the current links inside
     # it. This is necessary, otherwise we can end up having links in there
     # pointing to directories which no longer exist (on incremental builds).
     for link in os.listdir(target):
-      os.remove(os.path.join(target, link))
+      if utils.GuessOS() == 'win32':
+        # It seems like python on windows is treating pseudo symlinks to
+        # directories as directories.
+        os.rmdir(os.path.join(target, link))
+      else:
+        os.remove(os.path.join(target, link))
   else:
     os.makedirs(target)
   for source in args[1:]:
     # Assume the source directory is named ".../NAME/lib".
     (name, lib) = os.path.split(source)
     if lib != 'lib':
       name = source
     # Remove any addtional path components preceding NAME.
     (path, name) = os.path.split(name)
     if utils.GuessOS() == 'win32':
       source = os.path.relpath(source)
     else:
       source = os.path.relpath(source, start=target)
     exit_code = make_link(source, os.path.join(target, name))
     if exit_code != 0:
       return exit_code
   create_timestamp_file(options)
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))