Don't try to remove xcodebuild directory on Windows.

make.py

 # Copyright 2011 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # "Makefile" replacement to build skia for Windows.
 # More info at https://sites.google.com/site/skiadocs/
 #
 # Some usage examples:
 #   make clean
@@ skipping 33 matching lines @@
 
 def runcommand(command):
     print '> %s' % command
     if os.system(command):
         sys.exit(1)
 
 def MakeClean():
     """Cross-platform "make clean" operation."""
     cd(SCRIPT_DIR)
     rmtree(OUT_SUBDIR)
-    # clean up the directory that XCode (on Mac) creates
-    rmtree('xcodebuild')
 
 
 def CheckWindowsEnvironment():
     """For Windows: check environment variables needed for command-line build.
 
     If those environment variables are missing, try to set them.
     If environment variables can be set up, this function returns; otherwise,
     it displays an error message and exits.
     """
     # If we already have the proper environment variables, nothing to do here.
@@ skipping 99 matching lines @@
         print 'unknown platform (os.name=%s, sys.platform=%s); see %s' % (
             os.name, sys.platform, 'https://sites.google.com/site/skiadocs/')
         sys.exit(1)
     sys.exit(0)
 
 
 # main()
 Make(sys.argv[1:])