Platform support request: FreeBSD

We are in the early stages of adopting CodeQL in the OpenZFS project. The official repository currently supports both Linux and FreeBSD; and in the hopefully near future, it should also gain support for Windows and MacOS. Being able to run CodeQL on each platform to check the platform specific code for issues would be awesome. Unfortunately, FreeBSD is not one of the currently supported platforms:

https://codeql.github.com/docs/codeql-overview/system-requirements/

This issue is to request FreeBSD support, so that we will be able to run CodeQL scans on all OpenZFS platforms.