The CloudSync source code is currently part of the fcrepo-misc project on GitHub.
You can browse the source at the URL above or check it out via
git co git://github.com/cwilper/fcrepo-misc.git
To build it from the top level directory, run
mvn install
When the build completes, you will find the deployable war file in
fcrepo-cloudsync/fcrepo-cloudsync-service/target/