Bad choice of preprocessor variable name

[Doug Gwyn <gwyn>]

> You can have your cake and eat it: the new Amsterdam Compiler Kit C compiler
> would have sun defined and replace it by sun.

But this approach does not work with the large amount of existing code
that contains things like

#if u370 || pdp11

instead of

#if defined(u370) || defined(pdp11)

And in any case, it breaks

#define	sun( x )	(some-expression)

I don't think this problem has any really good solution.
ANSI C would forbid predefined things like this.