LibreSSL 3.5 compatibility

LibreSSL is now closer to OpenSSL 1.1 than OpenSSL 1.0. According to
https://undeadly.org/cgi?action=article;sid=20220116121253, this is the
intention of OpenBSD developers.

According to #40630, many special cases are needed to compile Tor against
LibreSSL 3.5 when using Tor's OpenSSL 1.0 compatibility mode, whereas only a
small number of #defines are required when using OpenSSL 1.1 compatibility
mode. One additional workaround is required for LibreSSL 3.4 compatibility.

Compiles and passes unit tests with LibreSSL 3.4.3 and 3.5.1.