[tlbuild] platform status

[Karl Berry]

1) Haven't heard from Vladimir, so I built sparc-solaris on one of
Nelson's machines (running 5.10).  I didn't extensively look into shared
libs, etc., but it seemed basically ok.

2) Likewise, I removed powerpc-aix, which was more or less the plan
since there seemed to be no users.  We'll see.

3) powerpc-linux, alpha-linux, x86_64-linux not updated yet.  All other
existing platforms have been.  Very quick job, everyone :).

4) There will certainly be more builds to come, but no critical changes
yet.  We'll see how it goes.

Thanks,
K