This is not actually full Tycho. Tycho requires Eclipse to build, and both
Eclipse and Tycho require Tycho itself to build (a previous version of Tycho
would be enough but we don't have it (yet).
We started with http://pkgs.fedoraproject.org/cgit/rpms/tycho.git/tree/tycho-bootstrap.sh
to understand which portions of Tycho may be built without Eclipse.