There's nothing on the wiki. Says "Welcome to the zfs wiki!"
also, the readme is the first thing anyone reads when they come to a repo, so it would make sense if that doc worked. the question is what I'm missing I guess
UPDATE: spl_config.h being in gitignore tipped me off that I need to configure spl first. PR at:
https://github.com/openzfsonosx/zfs/pull/630