attempt a CI build on illumos

[jclulow]

WIP; do not merge!

[nshalman]

In case you wanted to try to run stuff in an illumos VM, you might be interested in https://github.com/papertigers/illumos-vm from @papertigers.
e.g. https://github.com/fsnotify/fsnotify/pull/371/files#diff-faff1af3d8ff408964a57b2e475f69a6b7c7b71c9978cccc8f471798caac2c88R61-R74

The speed is kind of what you would expect from a VM, but I figured it was at least worth mentioning.

[papertigers]

Buildomat is probably much preferred here as I think it's capable of spinning up an illumos VM directly in AWS. My stuff will probably fill the free option for OSS out there as it's a macOS instance with virtualbox under the hood. I do plan to spend some time next week updating it. At which point moving it to the illumos org would also be preferred so we can put it in the GitHub marketplace or whatever it's called.