We no longer compile AFNI or SUMA for the SGI IRIX platform. We felt there was no demand for this, and you'll find the binaries on our site for SGI were last updated in Nov 2005.
In any case, we had trouble compiling SUMA for IRIX, and so didn't bother. You are the first one ever to ask for it. Or the first person to inquire after the SGI binaries in years (which is why we stoppped compiling them -- they were slowing down our plans for galactic domination).