Attempt at making git-drover work on Windows

git_common.py

 # 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.
 
 # Monkeypatch IMapIterator so that Ctrl-C can kill everything properly.
 # Derived from https://gist.github.com/aljungberg/626518
 import multiprocessing.pool
 from multiprocessing.pool import IMapIterator
 def wrapper(func):
   def wrap(self, timeout=None):
@@ skipping 803 matching lines @@
   # and deleted upstream branches).
   missing_upstreams = {}
   for info in info_map.values():
     if info.upstream not in info_map and info.upstream not in missing_upstreams:
       missing_upstreams[info.upstream] = None
 
   return dict(info_map.items() + missing_upstreams.items())
 
 
 def make_workdir_common(repository, new_workdir, files_to_symlink,
-                        files_to_copy):
+                        files_to_copy, symlink=None):
+  if not symlink:
+    symlink = os.symlink
   os.makedirs(new_workdir)
   for entry in files_to_symlink:
-    clone_file(repository, new_workdir, entry, os.symlink)
+    clone_file(repository, new_workdir, entry, symlink)
   for entry in files_to_copy:
     clone_file(repository, new_workdir, entry, shutil.copy)
 
 
 def make_workdir(repository, new_workdir):
   GIT_DIRECTORY_WHITELIST = [
     'config',
     'info',
     'hooks',
     'logs/refs',
     'objects',
     'packed-refs',
     'refs',
     'remotes',
     'rr-cache',
     'svn'
   ]
   make_workdir_common(repository, new_workdir, GIT_DIRECTORY_WHITELIST,
                       ['HEAD'])
 
 
 def clone_file(repository, new_workdir, link, operation):
   if not os.path.exists(os.path.join(repository, link)):
     return
   link_dir = os.path.dirname(os.path.join(new_workdir, link))
   if not os.path.exists(link_dir):
     os.makedirs(link_dir)
   operation(os.path.join(repository, link), os.path.join(new_workdir, link))