GNAT GPL 2011 on Lion

[Bill Findlay <yaldnif.w@blueyonder.co.uk>]

... Or the perils of being an early adopter.

I'm trying to run GNAT GPL 2011 under MacOS X 10.7, "Lion",
released yesterday.  The Ada compilation itself seem to be OK,
but I fall at this hurdle:

"gcc: error trying to exec 'as': execvp: No such file or directory"

This might be just a pathname issue, or something more serious.
Can anyone suggest a cause or a fix?

-- 
Bill Findlay
with blueyonder.co.uk;
use  surname & forename;