D3D7 -> WineD3D, 2nd attempt

[Stefan Dösinger]

> > WineD3D can't create a device without a Window. For DirectDraw and D3D7
> > running without a Window is valid, at least to a certain extent. The D3D
> > light test does so, and some games use this for some purposes. So I need
> > to do something for the case HWND == 0 or the d3d surface is not a
> > primary surface.
>
> Why not use the 'desktop' window to do it ? No idea what window will be
> used to display when not in Desktop mode (maybe the X root window ?).
This seems to be a good idea. Is this WND_DESKTOP or can I get it with 
GetDesktopWindow?

Stefan