Revert r13932, sys.stdout is not available.

tools/build.py

 #!/usr/bin/env python
 #
 # Copyright (c) 2011, 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.
 #
 
 import optparse
 import os
 import shutil
@@ skipping 298 matching lines @@
                               % os.environ['ANDROID_TOOLCHAIN'])
         toolsOverride = SetTools(arch, toolchainprefix)
         if toolsOverride:
           printToolOverrides = target_os != 'android'
           for k, v in toolsOverride.iteritems():
             args.append(  k + "=" + v)
             if printToolOverrides:
               print k + " = " + v
 
         print ' '.join(args)
-        # We redirect stderr to sys.stdout bacause the buildbot is not
-        # collecting stderr output.
-        process = subprocess.Popen(args, stderr=sys.stdout)
+        process = subprocess.Popen(args)
         process.wait()
         if process.returncode != 0:
           print "BUILD FAILED"
           return 1
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(Main())