mac: Make `find_sdk.py --print_sdk_path` much faster.

build/mac/find_sdk.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 """Prints the lowest locally available SDK version greater than or equal to a
 given minimum sdk version to standard output.
 
 Usage:
   python find_sdk.py 10.6  # Ignores SDKs < 10.6
@@ skipping 34 matching lines @@
   # Try using the toolchain in mac_files.
   mac_toolchain.SetToolchainEnvironment()
 
   job = subprocess.Popen(['xcode-select', '-print-path'],
                          stdout=subprocess.PIPE,
                          stderr=subprocess.STDOUT)
   out, err = job.communicate()
   if job.returncode != 0:
     print >> sys.stderr, out
     print >> sys.stderr, err
-    raise Exception(('Error %d running xcode-select, you might have to run '
-      '|sudo xcode-select --switch /Applications/Xcode.app/Contents/Developer| '
-      'if you are using Xcode 4.') % job.returncode)
-  # The Developer folder moved in Xcode 4.3.
-  xcode43_sdk_path = os.path.join(
+    raise Exception('Error %d running xcode-select' % job.returncode)
+  sdk_dir = os.path.join(
       out.rstrip(), 'Platforms/MacOSX.platform/Developer/SDKs')
-  if os.path.isdir(xcode43_sdk_path):
-    sdk_dir = xcode43_sdk_path
-  else:
-    sdk_dir = os.path.join(out.rstrip(), 'SDKs')
   sdks = [re.findall('^MacOSX(10\.\d+)\.sdk$', s) for s in os.listdir(sdk_dir)]
   sdks = [s[0] for s in sdks if s]  # [['10.5'], ['10.6']] => ['10.5', '10.6']
   sdks = [s for s in sdks  # ['10.5', '10.6'] => ['10.6']
           if parse_version(s) >= parse_version(min_sdk_version)]
   if not sdks:
     raise Exception('No %s+ SDK found' % min_sdk_version)
   best_sdk = sorted(sdks, key=parse_version)[0]
 
   if options.verify and best_sdk != min_sdk_version and not options.sdk_path:
     print >> sys.stderr, ''
     print >> sys.stderr, '                                           vvvvvvv'
     print >> sys.stderr, ''
     print >> sys.stderr, \
         'This build requires the %s SDK, but it was not found on your system.' \
         % min_sdk_version
     print >> sys.stderr, \
         'Either install it, or explicitly set mac_sdk in your GYP_DEFINES.'
     print >> sys.stderr, ''
     print >> sys.stderr, '                                           ^^^^^^^'
     print >> sys.stderr, ''
     return min_sdk_version
 
   if options.print_sdk_path:
-    print subprocess.check_output(['xcodebuild', '-version', '-sdk',
-                                   'macosx' + best_sdk, 'Path']).strip()
+    print subprocess.check_output(
+        ['xcrun', '-sdk', 'macosx' + best_sdk, '--show-sdk-path']).strip()
 
   return best_sdk
 
 
 if __name__ == '__main__':
   if sys.platform != 'darwin':
     raise Exception("This script only runs on Mac")
   print main()
   sys.exit(0)