This is great news! I'm gonna scope it out right now.
I just discovered this too. Having looked at it, it's because the UAMs are still using the libssl-dev 1.0 API. (Interestingly, though, the API calls were fixed in the afppasswd component of Netatalk in 2.2.6.) On Debian Stretch (9), I was able to work around by removing libssl-dev, and instead installing the libssl1.0-dev package. I don't know whether that's in the Raspbian repo or not, though. On Debian Buster (10), that package has been removed, so I had to add deb http://deb.debian.org/debian/...