Instead of accessing the surface with macdrv_get_surface_display_image.
-- v5: winemac: Remove now unnecessary cocoa window surface pointer. winemac: Push window surface image updates to the main thread. winemac: Create window surface CGImageRef on surface flush. winemac: Create a provider for the surface and a HBITMAP wrapping it. winemac: Remove unused macdrv_get_surface_display_image copy_data parameter.