Wine support for win64

[Stefan Dösinger]

> This summer Maarten Lankhorst did some basic work on win64 support but
> for the rest no work has been done it for a long time. I'm not sure
> what Maarten exactly did but but there is a lot of work to be done
> before it will run even a basic app.
I think we still have the problem that gcc doesn't support the calling
convention Win64 uses, so we can't compile a Wine that is compatible with
Win64 apps.

That may be fixed in gcc already though. I haven't checked since some time.