Revert "Revert "Upgrade to 5.0.71.48"" DO NOT MERGE

This reverts commit f2e3994fa5148cc3d9946666f0b0596290192b0e,
and updates the x64 makefile properly so it doesn't break that
build.

FPIIM-449

Change-Id: Ib83e35bfbae6af627451c926a9650ec57c045605
(cherry picked from commit 109988c7ccb6f3fd1a58574fa3dfb88beaef6632)
diff --git a/build/dir_exists.py b/build/dir_exists.py
new file mode 100755
index 0000000..70d367e
--- /dev/null
+++ b/build/dir_exists.py
@@ -0,0 +1,23 @@
+#!/usr/bin/env python
+# Copyright (c) 2011 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.
+"""Writes True if the argument is a directory."""
+
+import os.path
+import sys
+
+def main():
+  sys.stdout.write(_is_dir(sys.argv[1]))
+  return 0
+
+def _is_dir(dir_name):
+  return str(os.path.isdir(dir_name))
+
+def DoMain(args):
+  """Hook to be called from gyp without starting a separate python
+  interpreter."""
+  return _is_dir(args[0])
+
+if __name__ == '__main__':
+  sys.exit(main())