GCC headers and DJGPP port

[Joe Buck]

> Mike Stump wrote:
> > Well, I reviewed stddef.h, as it is one of the culprits.  After
> > reading it, I came to the conclusion that we can probably eject it
> > from the compiler safely.  It does seem like there is little reason to
> > have it in the compiler, better to be apart of newlib, of glibc, and
> > then all the complexity of it, and the heartache it causes, goes
> > away, permanently.
> 
> I like this idea. Any objections?

Wouldn't it break the SunOS4 port, or other ports where we're
bootstrapping from an ancient K&R environment and the C library
is highly nonstandard?

(I suppose stddef.h could be omitted only on the platforms where it
causes problems.)