Use an alt script to properly determine the OSX SDK version.

media/libyuv/build/mac/find_sdk_uxp.py

@@ -0,0 +1,12 @@
+#!/usr/bin/env python
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+import sys
+import subprocess
+
+def main():
+  return subprocess.call([sys.executable, "../webrtc/trunk/build/mac/find_sdk_uxp.py"] + sys.argv[1:])
+
+if __name__ == '__main__':
+  sys.exit(main())

media/webrtc/trunk/build/common.gypi

@@ -1169,7 +1169,7 @@
             # Enable Keystone auto-update support.
             'mac_keystone%': 1,
           }, { # else: branding!="Chrome" or buildtype!="Official"
-            'mac_sdk%': '<!(<(PYTHON) <(DEPTH)/build/mac/find_sdk.py <(mac_sdk_min))',
+            'mac_sdk%': '<!(<(PYTHON) <(DEPTH)/build/mac/find_sdk_uxp.py <(mac_sdk_path))',
             'mac_breakpad_uploads%': 0,
             'mac_breakpad%': 0,
             'mac_keystone%': 0,

media/webrtc/trunk/build/mac/find_sdk_uxp.py

@@ -0,0 +1,38 @@
+#!/usr/bin/env python
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+from __future__ import print_function
+import os
+import re
+import sys
+
+if sys.platform == 'darwin':
+  if len(sys.argv) <= 1:
+    print("find_sdk_uxp.py: error: Not enough arguments")
+    sys.exit(1)
+  else:
+    if os.path.isdir(sys.argv[1]):
+      SDK_PATH = sys.argv[1]
+    else:
+      print("find_sdk_uxp.py: error: Specified path does not exist or is not a directory")
+      sys.exit(1)
+
+  KNOWN_SDK_VERSIONS = ["10.7", "10.8", "10.9", "10.10",
+                        "10.11", "10.12", "10.13", "10.14",
+                        "10.15"]
+
+  REGEX = "^MacOSX(10\.\d+)\.sdk$"
+  SDK_VERSION = re.findall(REGEX, os.path.basename(SDK_PATH))
+
+  if not SDK_VERSION:
+    print("find_sdk_uxp.py: error: Could not determin the MacOS X SDK version")
+    sys.exit(1)
+
+  if SDK_VERSION[0] in KNOWN_SDK_VERSIONS:
+    print(SDK_VERSION[0])
+  else:
+    print("find_sdk_uxp.py: error: Unknown MacOS X SDK version")
+
+sys.exit(0)