Allow use of SKIA_OUT on Windows

gyp_skia

 #!/usr/bin/python
 
 # Copyright 2011 The Android Open Source Project
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This script is a wrapper which invokes gyp with the correct --depth argument,
 # and supports the automatic regeneration of build files if all.gyp is
 # changed (Linux-only).
@@ skipping 44 matching lines @@
 # be written.
 def get_output_dir():
 
   # SKIA_OUT can be any directory either as a child of the standard out/
   # directory or any given location on the file system (e.g. /tmp/skia)
   output_dir = os.getenv('SKIA_OUT')
 
   if not output_dir:
     return os.path.join(os.path.abspath(script_dir), 'out')
 
-  if (os.name != 'posix' or
-     (sys.platform.startswith('darwin') and 
+  if (sys.platform.startswith('darwin') and 
       (not os.getenv('GYP_GENERATORS') or 
-       'make' not in os.getenv('GYP_GENERATORS')))):
-    print 'ERROR: variable SKIA_OUT is not valid on Mac (using xcodebuild)' \
-          ' or Windows'
+       'make' not in os.getenv('GYP_GENERATORS'))):
+    print 'ERROR: variable SKIA_OUT is not valid on Mac (using xcodebuild)'
     sys.exit(-1);
 
   if os.path.isabs(output_dir):
     return output_dir
   else:
     return os.path.join(os.path.abspath(script_dir), output_dir)
 
 
 if __name__ == '__main__':
   args = sys.argv[1:]
@@ skipping 30 matching lines @@
   args.extend(['-Goutput_dir=.'])
 
   # By default, we build 'most' instead of 'all' or 'everything'. See skia.gyp.
   args.extend(['-Gdefault_target=most'])
 
   print 'Updating projects from gyp files...'
   sys.stdout.flush()
 
   # Off we go...
   sys.exit(gyp.main(args))