remove noop backend and noop output

[bl4ckb0ne]

Fix for swaywm/wlroots#3227

[emersion]

Well we still need to keep the noop output, but we can replace it with a headless output.

[bl4ckb0ne]

Pushed a v2 of the patch. I put 800x600 as the headless output size randomly, let me know if you'd like a different size.

[emersion]

Hm for some reason the headless output now shows up in swaymsg -t get_outputs. This was not the case for the noop one. It also shows up in wayland-info btw.

Also need to remove #include <wlr/backend/noop.h> from sway/server.c.

[bl4ckb0ne]

Is it something we don't want?

[emersion]

Yeah, we don't want this internal implementation detail to be exposed to our users. Users will be confused if they see this output that isn't supposed to exist.

[emersion]

I think this happens because the sway_output is enabled for some reason? It shouldn't get enabled.

[emersion]

Hm maybe this is an issue with wlroots, where wlr_output.enabled == true for headless outputs but not for noop. But I'm confused, I see noop outputs are marked as enabled in wlroots with wlr_output_update_enabled…

[emersion]

Code LGTM! Can you squash these commits together? Starting Sway with just the first one applied will segfault.

[bl4ckb0ne]

Done! I also added a bit of explaination in the commit message.

[emersion]

Excellent, thanks!