Use os.rmdir() for symlinks on windows.

dart/tools/make_links.py

Index: dart/tools/make_links.py
diff --git a/dart/tools/make_links.py b/dart/tools/make_links.py
index ca464ff8e5148d4c4d0f27f892194c3001bbc07e..1893f2d41ac6906022423e0b67a106e89196e888 100644
--- a/dart/tools/make_links.py
+++ b/dart/tools/make_links.py
@@ -67,7 +67,12 @@ def main(argv):
     # 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:]: