This MR is the second attempt at !208 (closed).
SSL_OP_NO_CLIENT_RENEGOTIATION is opaque which is not compatible with the OpenSSL 1.0.2 and earlier code path in
SSL_OP_NO_RENEGOTIATION is not yet defined for the newer OpenSSL code path in
So with OpenSSL 1.1.0 and later if
SSL_OP_NO_RENEGOTIATION is undefined and
SSL_OP_NO_CLIENT_RENEGOTIATION is defined then define the former as the latter. This will allow the build to succeed with LibreSSL 3.7.2 and in the future when newer LibreSSL versions add
SSL_OP_NO_RENEGOTIATION that code path will then be used automatically.