BUILD/MEDIUM: Fixing the build using LibreSSL

Fixing the build using LibreSSL as OpenSSL implementation.
Currently, LibreSSL 2.4.4 provides the same API of OpenSSL 1.0.1x,
but it redefine the OpenSSL version number as 2.0.x, breaking all
checks with OpenSSL 1.1.x.
The patch solves the issue checking the definition of the symbol
LIBRESSL_VERSION_NUMBER when Openssl 1.1.x features are requested.
2 files changed