Add mac toolchain script support to find_sdk script.

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 22 matching lines @@
                     action="store", type="string", dest="sdk_path", default="",
                     help="user-specified SDK path; bypasses verification")
   parser.add_option("--print_sdk_path",
                     action="store_true", dest="print_sdk_path", default=False,
                     help="Additionaly print the path the SDK (appears first).")
   options, args = parser.parse_args()
   if len(args) != 1:
     parser.error('Please specify a minimum SDK version')
   min_sdk_version = args[0]
 
+  # Try using the toolchain in mac_files.
+  sys.path.append(os.path.dirname(os.path.dirname(__file__)))
+  import mac_toolchain

[erikchen, 2016/03/30 17:39:55]

I've seen python files in our code base that would have these two lines at the
top of the file, along with imports. Would that be cleaner?

[justincohen, 2016/03/30 21:14:26]

Done.

+  mac_toolchain_dir = mac_toolchain.GetToolchainDirectory()
+  if mac_toolchain_dir:
+     os.environ['DEVELOPER_DIR'] = mac_toolchain_dir

[erikchen, 2016/03/30 17:39:55]

2 space indent?

Given that this logic is also present in build/gyp_environment.py, should we
make a new method in mac_toolchain_dir? Mostly trying to avoid duplicated static
strings.

[justincohen, 2016/03/30 21:14:26]

Done.

+
   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)
@@ skipping 31 matching lines @@
                                    'macosx' + best_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)