62857757a9
Specifically, set WAYLAND_DISPLAY only once and reuse the var, don't export it to weston itself (even though it's ignored because we explicitly select the headless backend instead of auto), use long option names for added clarity, and replace deprecated `--use-gl` with `--renderer=gl`. Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36485>