Detect cygwin as Win32 for the purposes of running GN and downloading from google storage.

gn.py

 #!/usr/bin/env python
 # Copyright 2013 The Chromium Authors. All rights reserved.
 # 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 around the GN binary that is pulled from Google
 Cloud Storage when you sync Chrome. The binaries go into platform-specific
 subdirectories in the source tree.
 
 This script makes there be one place for forwarding to the correct platform's
@@ skipping 25 matching lines @@
       return cur
     up_one = os.path.dirname(cur)
     if up_one == cur:
       return None  # Reached the top of the directory tree
     cur = up_one
 
 
 def RunGN(sourceroot):
   # The binaries in platform-specific subdirectories in src/tools/gn/bin.
   gnpath = sourceroot + '/tools/gn/bin/'
-  if sys.platform == 'win32':
+  if sys.platform in ['win32', 'cygwin']:

[M-A Ruel, 2013/12/05 14:37:58]

if sys.platform in ('cygwin', 'win32'):

     gnpath += 'win/gn.exe'
   elif sys.platform.startswith('linux'):
     gnpath += 'linux/gn'
   elif sys.platform == 'darwin':
     gnpath += 'mac/gn'
   else:
     raise PlatformUnknownError('Unknown platform for GN: ' + sys.platform)
 
   return subprocess.call([gnpath] + sys.argv[1:])
 
 
 def main(args):
   sourceroot = FindSourceRootOnPath()
   if not sourceroot:
     print >> sys.stderr, '.gn file not found in any parent of the current path.'
     sys.exit(1)
   return RunGN(sourceroot)
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))