Gentoo/Alt is a Gentoo Linux project created to manage porting the Portage framework and other features to other operating systems, such as Mac OS X and the free BSDs. Gentoo/Alt was set up by Pieter Van den Abeele and Daniel Robbins after Pieter Van den Abeele founded Gentoo for Mac OS X.
Read more about Gentoo/Alt: Gentoo For Mac OS X, Gentoo/*BSD, Gentoo GNU Hurd, Gentoo Prefix, Portaris