need help with builtin function prototypes

[DJ Delorie]

> I don't know about using reference types, but there are several math
> builtins that "return" multiple values, the extra ones via pointer
> arguments.  E.g. see frexp, lgamma_r, modf, remquo and/or sincos.

Like I said, I'm kinda locked into the syntax.  People have been using
these builtins for many years now.  Everything was fine when we
expanded the builtins to insns before optimization, and we could block
optimizations using RTL, but we don't have that option with tree
optimizations.