> This did raise one issue of should we be using #ifdef lowercase arch name or 
> including opt_archname, and using uppercase arch name,
> IE:
> #ifdef cats
> or
> #include "opt_cats.h"
> #ifdef CATS
> 
> I prefer the first as it avoids having to have lots of defopts (but then 
> richard has suggested hiding them in one .h file.)  Any preferences, I say 
> noting that I already tweaked locore.S to get cats building, but I'm happy to 
> revert it back.
> 

The principal advantage of defopt over -D<foo> is that the former will 
correctly rebuild without a "make clean" if the defines change.  However, 
the name of the machine is somewhat unlikely to change, so...

Generally, I prefer uppercase for macros (which includes defines).

R.