recognise certificate and private key options.
+=item SSL_CONF_FLAG_REQUIRE_PRIVATE
+
+If this option is set then if a private key is not specified for a certificate
+it will attempt to load a private key from the certificate file when
+SSL_CONF_CTX_finish() is called. If a key cannot be loaded from the certificate
+file an error occurs.
+
=item SSL_CONF_FLAG_SHOW_ERRORS
indicate errors relating to unrecognised options or missing arguments in