xf86-video-sunbw2 can't possibly build at present - it needs xf86Version.h, which was removed 2008-08-15 with commit 544bfd06663ff71bc5275459cf74a3557530544 - it's possible anyone still running such a machine hasn't tried putting a recent Xorg on it.
Resolution: either declare this driver dead and remove it, or fix it up.
The driver has already been removed from Ubuntu and Debian:
On Sat, Jan 30, 2010 at 19:48:18 -0800, email@example.com wrote:
> Resolution: either declare this driver dead and remove it, or fix it up.
It has been taken out of the modular/build.sh