Fix: Use -C instead of --git-dir.

recipe_engine/package.py

 # Copyright 2015 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.
 
 import ast
 import collections
 import contextlib
 import copy
 import functools
 import itertools
@@ skipping 181 matching lines @@
     self.path = path
 
   def __str__(self):
     return ('GitRepoSpec{project_id="%(project_id)s", repo="%(repo)s", '
             'branch="%(branch)s", revision="%(revision)s", '
             'path="%(path)s"}' % self.__dict__)
 
   def run_git(self, context, *args):
     cmd = [self._git]
     if context is not None:
-      cmd += ['--git-dir', os.path.join(self._dep_dir(context), '.git')]
+      cmd += ['-C', self._dep_dir(context)]
     cmd += list(args)
 
     logging.info('Running: %s', cmd)
     return subprocess.check_output(cmd)
 
   def checkout(self, context):
     dep_dir = self._dep_dir(context)
     logging.info('Freshening repository %s', dep_dir)
 
     if not os.path.isdir(dep_dir):
@@ skipping 512 matching lines @@
   >>> d = { 'x': 1, 'y': 2 }
   >>> sorted(_updated(d, { 'y': 3, 'z': 4 }).items())
   [('x', 1), ('y', 3), ('z', 4)]
   >>> sorted(d.items())
   [('x', 1), ('y', 2)]
   """
 
   d = copy.copy(d)
   d.update(updates)
   return d