- Not all Xcode versions feature a release number. Update

tools/gyp/find_mac_gcc_version.py

 #!/usr/bin/env python
 # Copyright (c) 2013, 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 re
 import subprocess
 import sys
 
 def main():
   job = subprocess.Popen(['xcodebuild', '-version'],
                          stdout=subprocess.PIPE,
                          stderr=subprocess.STDOUT)
   stdout, stderr = job.communicate()
   if job.returncode != 0:
     print >>sys.stderr, stdout
     print >>sys.stderr, stderr
     raise Exception('Error %d running xcodebuild!' % job.returncode)
-  matches = re.findall('^Xcode (\d+)\.(\d+)\.(\d+)$', stdout, re.MULTILINE)
+  matches = re.findall('^Xcode (\d+)\.(\d+)(\.(\d+))?$', stdout, re.MULTILINE)
   if len(matches) > 0:
     major = int(matches[0][0])
     minor = int(matches[0][1])
 
     if major >= 4:
       return 'com.apple.compilers.llvmgcc42'
     elif major == 3 and minor >= 1:
       return '4.2'
     else:
       raise Exception('Unknown XCode Version "%s"' % version_match)
   else:
     raise Exception('Could not parse output of xcodebuild "%s"' % stdout)
 
 if __name__ == '__main__':
   if sys.platform != 'darwin':
     raise Exception("This script only runs on Mac")
   print main()