Used for winex11 and later will be used in winemac and winewayland.
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v3: win32u: Pass the shape bitmap info and bits to window_surface flush.
win32u: Update the window surface shape with color key and alpha.
win32u: Use a 1bpp bitmap to store the window surface shape bits.
win32u: Introduce a new window surface helper to set window shape.
win32u: Pass whether window is shaped to drivers WindowPosChanging.
win32u: Pass the window surface rect for CreateLayeredWindow.
win32u: Split a new create_window_surface helper from apply_window_pos.
win32u: Move offscreen window surface creation fallback.
https://gitlab.winehq.org/wine/wine/-/merge_requests/5962