Native FreeBSD and OpenBSD testing on CI

[gnzlbg]

https://builds.sr.ht/ offers native (no qemu emulation) FreeBSD and OpenBSD CI services. These are currently free and invite only, but invites can be requested at sir@cmpwn.com . They plan to offer these as paid services in the future at $2, $5, and $10 / month price points depending on the plan.

This is currently how https://github.com/swaywm/wlroots is tested on these platforms.

Maybe we should give these a try.

[asomers]

https://cirrus-ci.com/ also offers FreeBSD CI services (and Windows, OSX, and Linux too).

[asomers]

What would it take to get this done? Cirrus CI is pretty easy to use.