> From: Alistair Crooks <azcb0@amdahl.com>
> ...
> Can we at least start to use __unix__, please? I do not want to have to
> try to explain to imake, for example, to try to compile unix.c, rather
> than 1.c. imake is borken, you say? Right. But too much depends on it to
> change its behaviour. And, just for the record, I loathe imake with a
> vengeance.
> ...

Please see the discussion since Saturday on tech-userlevel, Re: -Dunix
predefine.

Have you ever actually seen this problem?  Or is this just hypothetical?

Because, if it's hypothetical, I think it's also a "cannot happen".

You see, apparently every system except NetBSD predefines unix == 1.

As a result, this symbol is reserved in the namespace. Programs use it,
and it doesn't pollute the namespace to define it because no portable program
can use it for anything else (without an #undef).

If any of those systems do it just for C programs and not for Makefile
templates then we have to be more clever.