Sometimes you just need someone to tell you you're an idiot 🙂
Thank you Patrick! I mean it.
It all came down to my missing knowledge. I was trying to link openssl in the my app, but when I built openssl I didn't change target ios.
Now I've rebuilt openssl, and the error is gone. (Some other errors came up, but that is for another day)
Thanks again Patrick. Sometimes I just need a kick in the plums 😉