Add infrastructure to download golang and build AppRTC collider.

build_mercurial_local.py

+#!/usr/bin/python
+# Copyright 2014 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.
+
+"""Builds a local mercurial (hg) copy.
+
+This is used by the go toolchain.
+"""
+
+import os
+import shutil
+import subprocess
+import sys
+
+import utils
+
+
+def main():
+  if not os.path.exists('mercurial'):
+    return 'Expected mercurial at %s.' % os.path.abspath('mercurial')
+
+  os.chdir('mercurial')
+
+  if utils.GetPlatform() == 'win':
+    subprocess.check_call(['python', 'setup.py', '--pure', 'build_py', '-c',
+                           '-d', '.', 'build_ext',
+                           '-i', 'build_mo', '--force'])
+    with open('hg.bat', 'w') as put_hg_in_path:
+      # Write a hg.bat since the go toolchain expects to find something called
+      # 'hg' in the path, but Windows only recognizes executables ending with
+      # an extension in PATHEXT. Writing hg.bat effectively makes 'hg' callable
+      # if the mercurial folder is in PATH.
+      mercurial_path = os.path.abspath('hg')
+      put_hg_in_path.write('python %s %%*' % mercurial_path)
+  else:
+    subprocess.check_call(['make', 'local'])
+
+if __name__ == '__main__':
+  sys.exit(main())