DOS/Windows-related changes in the include subdirectory

[Eli Zaretskii]

> >    If you want me to change the definitions, please send me the
> >    definitions from the GCC sources (I don't have them installed).
> 
> Since I'm responsible for the above mentioned GCC changes, I can
> help you Eli if you are going to make the changes.

It's up to Ian.  If he wants me to change the macros to make them more
close to what GCC uses, I will do it.  I used these macros (with minor
changes, as the case in point might dictate) in quite a few packages
that now include them in official GNU releases, although GCC is
obviously not one of them.