They're tricky tricky tricky tricky.

So we can be sure it keeps working.

The last commit changed the environment, so we need to regenerate
the config cache.

Both sbbs-noskeeters and sbbs-build create sbbs-build.tgz
Hopefully this fixes it and doesn't just break it worser.

This should hopefully surface whatever is corrupting the file.

This should help debug if multiple jobs are writing the same archives.

artifacts before deleting temp files. :(

Also, allow tests to run as soon as jsdoor is done, and don't use
the artifact file, use the local copy instead.

Only on freebsd-amd64 now though... no need to leave stuff laying
everywhere.

hoping this doesn't leave an empty zip file laying aorund.

This basically just moves the download of sbbs-build from the test
phase to the build phase, so shouldn't result in any speedup.

This will allow sbbs-build to run in parallel with scfg etc.

Search in both /usr/local (Homebrew) and /opt/local (MacPorts) for
libraries.

Also, have the name of GNU make be an in option in CI so we can use
the Apple-provided make.