winewayland.drv: Add alpha-modifier-v1 protocol to support change alpha by WAYLAND_SetLayeredWindowAttributes. @afrantzis @rbernon The attachment is the test source code on Windows and the corresponding generated test program. [test-layered-alpha.cpp](/uploads/dba6d38e8990978d4bde562011c85995/test-layered-alpha.cpp) [test-layered-alpha.exe](/uploads/bba6c165533d56ca85af9d461e488b03/test-layered-alpha.exe) The test program runs as shown in the figure below. {width=505 height=543} The purpose of the patch is that when adjusting the Alpha slider in the figure, the transparency of the window changes accordingly. -- v4: winewayland.drv: Add WAYLAND_UpdateLayeredWindow and add support for changing alpha using the alpha-modifier-v1 protocol. winewayland.drv: Add alpha-modifier-v1 protocol to support change alpha by WAYLAND_SetLayeredWindowAttributes. https://gitlab.winehq.org/wine/wine/-/merge_requests/10848