>Unfortunately SunOS-4 make execs /bin/arch (among other things), using
>that explicit path.

I think is lossage due to the order of  emul prefixing:
it isn't being applied to the  target of the symlink.

If we did that (which in this case we clearly should), everything
would Just Work.

I'm guessing that the LOOKUP is following the pathname to the wrong
place. Is it possible our SunOS emul isn't doing prefixing on all
variants of exec()? 

Drat.  I just tried to duplicate this on a pmax with an Ultrix binary,
and i got a "locking against myself" panic...