Re: bignums and native back end

> x / 1 = x
> x / ~1 = ~x
>
> x - x = 0 (* probably rare *)

Got 'em. And a few others. The code for simplification of primapps in
atoms/prim.fun is getting pretty big (400 lines). It'd be nice if someone else
reads through it whenever I put out the next rpm (RSN).