Add support for a .gclient_ignore which tells gclient to ignore versioning of...

gclient.py

 #!/usr/bin/python
 #
 # Copyright 2008 Google Inc.  All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #      http://www.apache.org/licenses/LICENSE-2.0
 #
@@ skipping 740 matching lines @@
     Raises:
       Error: if can't get URL for relative path.
     """
     # Only update if git is not controlling the directory.
     checkout_path = os.path.join(self._root_dir, self.relpath)
     git_path = os.path.join(self._root_dir, self.relpath, '.git')
     if os.path.exists(git_path):
       print("________ found .git directory; skipping %s" % self.relpath)
       return
 
+    # Also skip any diretories maked to be ignored explicitly with
+    # .gclient_ignore.
+    ignore_path = os.path.join(self._root_dir, self.relpath, '.gclient_ignore')
+    if os.path.exists(ignore_path):
+      print("________ found .gclient_ignore; skipping %s" % self.relpath)
+      return
+
     if args:
       raise Error("Unsupported argument(s): %s" % ",".join(args))
 
     url = self.url
     components = url.split("@")
     revision = None
     forced_revision = False
     if options.revision:
       # Override the revision number.
       url = '%s@%s' % (components[0], str(options.revision))
@@ skipping 965 matching lines @@
 
 if "__main__" == __name__:
   try:
     result = Main(sys.argv)
   except Error, e:
     print >> sys.stderr, "Error: %s" % str(e)
     result = 1
   sys.exit(result)
 
 # vim: ts=2:sw=2:tw=80:et: