bug#14361: Building guile 2.0.9 under mingw + msys

[Eli Zaretskii]

> From: Andy Wingo <address@hidden>
> Cc: address@hidden,  address@hidden
> Date: Tue, 21 Jun 2016 17:06:05 +0200
> 
> Let's give it a go!  I understand that you do not want to work with
> gnulib.  That's a negative from a Guile POV -- but it's not a
> deal-breaker.

I have nothing against Gnulib, but in this case their solution is
simply not up to speed.

> To that end I hesitate about including a bunch more stuff in
> posix.c.  Must it all be there, or would it be possible to move some
> of it out to our own gnulib-like mingw-w32.[ch] or something?

Most of it is already on a separate file, w32-proc.c (see the diffs).
I could take the macros at the beginning of posix.c and put them on a
separate .h file, if that would be better.  The rest of the changes in
posix.c are just moving #ifdef's around, more or less, and a few small
fragments of code, not unlike in other places.  I could, of course,
put them in separate functions, but the advantage of the patch I
pointed to is that it's well tested.

Thanks.