Burger menu doesn't render when using Wayland

[crabctrl]

Using Lagrange 1.11.1 + SDL 2.0.16 + Sway with SDL_VIDEODRIVER=wayland, clicking the burger menu does open a window (!!!) but the contents of the window are not rendered, instead just displaying the background colour.

As a side note, upon release of SDL 2.0.22 (which is due to be released very soon), Wayland will be the default video driver rather than X11. This means Wayland will be used even if SDL_VIDEODRIVER is unset.

[skyjake]

Hopefully SDL 2.0.22 + Wayland will behave more like the other windowing systems, but ultimately the solution here is to use an actual GUI toolkit like GTK with "native" menus. Using GLib and GTK may anyway be required to work correctly under Flatpak, for example, and D-Bus is needed for other things, too. (See #282, #245.)

As a workaround, when running under Wayland, the app's popup menu feature can be disabled with a build option (see Known Issues: https://gmi.skyjake.fi/lagrange).

[skyjake]

SDL 2.0.22 (which is due to be released very soon), Wayland will be the default video driver rather than X11.

Looks like Wayland-by-default got postponed due to regressions in various games.