The Gentoo RepRap Overlay aims to add all the patches and tools you need to run your ReRap under Gentoo Linux. My RepRap is a RepStrap and its still very much under construction. This overlay contains my tries on running all kinds of RepRap related software on Gentoo Linux. The ebuilds that don't have a keyword probably won't compile or have missing deps. The ~x86 ones compile, but there are some untested bin/library combinations in them. Programming a (sanguino) RepRap motherboard and basic interfacing with x11-apps/replicatorg-bin and x11-apps/reprap-bin should be ok. The dev-embedded/arduino ebuild has sanguino and reprap USE flags that you may use to patch the ebuilds /usr/share/arduino-XXXX dir with the needed libraries.