libtool, autoconf, automake and perl are no longer dependencies of
neovim and doesn't need to be installed in CI anymore. The dependencies
and the commit that removed them as dependencies are the following:
libtool: b05100a9ea
perl: 20a932cb72
autoconf+automake: e23c5fda0a
Detect if on CI by checking that the CI environment variable is set to "true".
This is a common pattern among CI providers, including github actions and
cirrus.
dispatch.sr.ht is being deprecated, meaning that using sourcehut CI
won't be possible (see https://github.com/neovim/neovim/issues/19609).
Since Github Actions doesn't provide any BSD runners an external service
is required and Cirrus CI seems like a good replacement for sourcehut.
Initially experimented with using FreeBSD and OpenBSD virtual machines
in GitHub Actions, but Cirrus has been a much better fit with better
performance, logs and overall experience.
Failing tests are automatically skipped on FreeBSD regardless if it's on
CI or not. Ideally these tests should only be skipped in CI with the
help of `isCI` helper function. Unfortunately, the tests don't recognize
the environment variable CIRRUS_CI even if it's set manually. This
workaround is good enough for the time being, but we might want to only
skip tests when using the CI (or even better, fix the failing tests).
Closes: https://github.com/neovim/neovim/issues/19609
