It has to update the whole surface, so NULL must be passed to 
x11_copy_to_screen. Fixes a regression in Red Alert.

It indicates support of colorkey transparency on textures, so set it because 
wined3d supports it. Fixes transparency problems in Forsaken.

There's no need to do that with the nvts and opengl ffp fixed function
fragment pipeline, it's perfectly well defined in GL which one takes
effect. This removes a few more troubles when switching between
shaders and arbfp.

ARB and GLSL don't need that. If a shader backend like atifs or nvts
need it in the future, the shader backend should deal with that rather
than the ffp pipeline.

Half Life 2 uses D3DFMT_X8R8G8B8 for the back buffer, but macos
supports aux buffers only on D3DFMT_A8R8G8B8. I think having aux
buffers is more important right now than having a precise alpha
match.