[tex-k] patch to fix dvips crashes on macos with clang

[Akira Kakuto]

Dear Tomas,

> This change looks good.  I wonder if there are any other such places in the 
> code; I remember using that trick a few places.

I sent Karl a sample patch, including color.c, about 2 months ago.
He is busy, but I believe that he will review my patch  and
will improve dvips sources soon.

Thanks,
Akira