Don't try to chmod symlinks.

buildbot/buildbot_lib.py

 #!/usr/bin/python
 # Copyright (c) 2012 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import optparse
 import os.path
 import shutil
 import subprocess
 import stat
@@ skipping 341 matching lines @@
   Does not mask failures, although it does retry a few times on Windows.
   """
   Retry(_RemoveDirectory, path)
 
 
 def RemovePath(path):
   """Remove a path, file or directory."""
   if os.path.isdir(path):
     RemoveDirectory(path)
   else:
-    os.chmod(path, stat.S_IWUSR)
+    if os.path.isfile(path) and not os.access(path, os.W_OK):
+      os.chmod(path, stat.S_IWUSR)
     os.remove(path)
 
 
 # This is a sanity check so Command can print out better error information.
 def FileCanBeFound(name, paths):
   # CWD
   if os.path.exists(name):
     return True
   # Paths with directories are not resolved using the PATH variable.
   if os.path.dirname(name):
@@ skipping 305 matching lines @@
   #   Otherwise these go back to the preamble.
   with Step('summary', status):
     if status.ever_failed:
       print 'There were failed stages.'
     else:
       print 'Success.'
     # Display a summary of the build.
     status.DisplayBuildStatus()
 
   sys.exit(status.ReturnValue())