Hi,

This gets drawterm to compile and not segfault under x86_64 mingw-w64.
Tested on Wine and MSYS2.

I noticed that the win32-386 and posix-386 directories are nearly the
same (some asm preprocessor metarule in the win32-386 Makefile?), so I
used posix-amd64 for libmachdep.a instead of making a new directory.
I'll leave keeping or removing win32-386/ up to discussion.

Thanks,
Amavect