[tlbuild] some executable inconsistencies

[Karl Berry]

    i386-kfreebsd, amd64-kfreebsd:
     (*) "xasy" is a symlink to "asy", instead of to "../../texmf/asymptote/GUI/xasy.py"

Thanks, I'll fix that in svn.  Alan, can you propagate that change into
your setup?

    i386-cygwin:
     (*) missing symlink: xasy -> ../../texmf/asymptote/GUI/xasy.py

I'm not sure that X runs on Cygwin.  Ken?

Olaf is aware of the need to rebuild Irix.  If he succeeds, great, if
not, we'll just remove that platform before the release.

All others are known and not a problem.  The outdated xetex's are
because I haven't yet had a chance to check in all the binaries that
people have kindly immediately rebuilt!  It hasn't even been 24 hours :).
They're coming ...

Best,
karl