Better detection of OpenSSL/LibreSSL features availability

[rgacogne]

• Program: Authoritative, Recursor, dnsdist
• Issue type: Feature request

Short description

We currently detect the availability of some OpenSSL / LibreSSL features based on the version number, which is tricky because LibreSSL does weird things with OPENSSL_VERSION_NUMBER. It was suggested in #8733 that we could do proper detection of some functions during configure instead, and that we don't need to set up thread-specific callbacks with recent enough (>= 0x2090100fL) versions of LibreSSL (which we do in auth, dnsdist and rec at the moment).