[RFE] Libdecor support

[grulja]

Apparently libdecor now has gtk plugin so it might be worth at least giving it a shot and see if we can implement our decorations with it.

Link: https://gitlab.gnome.org/jadahl/libdecor

[polter-rnd]

A good idea. You can see a similar use case in FLTK: https://github.com/fltk/fltk/blob/master/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx

[orowith2os]

Does GTK3 support Wayland subsurfaces and wl_shm yet? IIRC those were a requirement for having it perform at its best, along with Vulkan support (SDL games).

Plus, if QGnomePlatform were to adopt libdecor, wouldn't it make sense to upstream it to QT instead? They could definitely use it.