Try to work around LibreSSL 3.9.0 dropping EVP_add_digest().

[demonfoo]

No description provided.

[h-vn]

Thanks! This is indeed needed. There's also a new rule in .gitignore file. Should that go in too? If yes, please let me know what creates .sw? files.

[demonfoo]

The .sw? files are Vim swapfiles. It was easier to have git just ignore them while I was working with the repo.

Edit: I would think anyone using Vim to work on the repo would want this, so unless there's a specific concern I'd encourage keeping it.

Edit 2: Actually that probably should have been .*.sw?, come to think of it...