[PATCH v2 0/5] MR4565: winex11: Use helpers to attach / detach / destroy client windows.

[Rémi Bernon]

After some discussion on https://gitlab.winehq.org/wine/wine/-/merge_requests/4533, this refactors how child_window are handled to make it easier to decouple them from the whole_window, and eventually have multiple detached child_window for some Vulkan use case (possibly also GL).

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  v2: winex11: Introduce a new attach_client_window helper.
      winex11: Introduce a new destroy_client_window helper.
      winex11: Introduce a new detach_client_window helper.
      winex11: Get rid of ref held from the HWND to its Vk surface.
      winex11: Keep the client window colormap on the GL drawable.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/4565