Contributed by Nik Clayton
<nik@FreeBSD.ORG>.
Once you have synchronised your local source tree against a particular
version of FreeBSD (stable, current and so on) you
must then use the source tree to rebuild the system.
Currently, the best source of information on how to do that is a tutorial available from http://www.nothing-going-on.demon.co.uk/FreeBSD/make-world/make-world.html.
A successor to this tutorial will be integrated into the handbook.