Allow specifying wayland display

[Cloudef]

Would be nice to allow specify wayland display with env variable such as EXTEST_WAYLAND_DISPLAY. So you can expose the env variable to the library but not the main process or any child processes.

[Supreeeme]

What issue are you running into without this?

[Cloudef]

I don't want to expose WAYLAND_DISPLAY to Steam/Proton, but I want extest to still work. That is I want Steam/Proton to actually run X11 versions of the programs.

[Supreeeme]

As far as I'm aware Steam/Proton is still 100% X11 anyway.

[Cloudef]

It's possible to launch linux apps from steam as well though. Extest does not work with gamescope, so I need to give it my hyprland's WAYLAND_DISPLAY, now this causes the wayland apps to spawn outside of gamescope, so I wish I could just set WAYLAND_DISPLAY for extest only.