Please, if you run into issues building stuff against LibreSSL, let us know, otherwise we can't fix them.
Some upstreams are helpful and cooperative, but there's too many #ifdefs out there, many of them not so well done and they typically won't ever be removed. We still strive to be as compatible as possible. If something doesn't compile against LibreSSL, that's a LibreSSL bug, not an upstream bug.