--- a/media/webrtc/trunk/build/mac/find_sdk.py
+++ b/media/webrtc/trunk/build/mac/find_sdk.py
@@ -79,17 +79,17 @@ def main():
   if options.print_sdk_path:
     print subprocess.check_output(
         ['xcrun', '-sdk', 'macosx' + best_sdk, '--show-sdk-path']).strip()
 
   return best_sdk
 
 
 if __name__ == '__main__':
-  if sys.platform == 'darwin' or os.environ.get('MOZ_AUTOMATION') != '1':
+  if sys.platform == 'darwin' and os.environ.get('MOZ_AUTOMATION') != '1':
     print main()
   else:
     # Mozilla builds cross-compile on Linux or install an SDK from tooltool, so
     # return some fake data to keep the build system happy. These values aren't
     # used anywhere.
     print "."
     print "."
   sys.exit(0)