As the summary states, media-libs/mesa-7.8_rc1 no longer contains a DRI driver for sunffb. As such, the current ebuild causes mesa's configure script to fail if sunffb is in VIDEO_CARDS because it's trying to find a driver that doesn't exist in its source. I'll attach an updated ebuild with the sunffb parts removed momentarily. If you want the logs, I can post them but they didn't seem to be overly useful in this case.
Created attachment 224793 [details] Updated mesa ebuild with sunffb statements removed.
Updated with addtion of new rc version.
Works great here, thanks!