Support the Repo (a tool from google) way to work

http://source.android.com/source/git-repo.html

Installing Repo
$ curl http://android.git.kernel.org/repo > ~/bin/repo
$ chmod a+x ~/bin/repo
$ mkdir working-directory-name
$ cd working-directory-name
$ repo init -u git://android.git.kernel.org/platform/manifest.git

Synchronizing your client
To synchronize the files for all available projects:
$ repo sync

To synchronize the files for selected projects:
$ repo sync project1 project2 ...