[DGD] DGD For MSys, mark 2

[Felix A. Croes]

I've chosen to push my changes to your changes to the msys branch of
the official repository.  You can read my commentary in the commit
message.

Jared Maddox <absinthdraco at gmail.com> wrote:

>[...]
> What about the comment above ifeq ($(OS),Windows_NT) ? I worry that
> without it, the reason for putting that in such an inconsistent place
> may be forgotten.

You are right, it would be good to have a brief comment about the location
in the Makefile.

What remains to be done:

 - fix the issue where make clean doesn't clean
 - get precompiling to work (involves changing comp/Makefile and
   lpc/Makefile)

A related issue that you may also want to tackle: a.exe is a poor name
for the executable on Windows, and a.out is gradually becoming a poor
name on unix (few remember or care that it's the default linker output).
It would be a good idea to change the default binary to dgd on unix, and
dgd.exe on Windows.

Regards,
Felix Croes