Merge pull request #479 from remicollet/patch-1

SSL_CTX_set_max_proto_version requires openssl 1.1

Author: mpenick

src/ssl/ssl_openssl_impl.cpp

@@ -539,8 +539,10 @@ OpenSslContext::OpenSslContext()
     , trusted_store_(X509_STORE_new()) {
   SSL_CTX_set_cert_store(ssl_ctx_, trusted_store_);
   SSL_CTX_set_verify(ssl_ctx_, SSL_VERIFY_NONE, ssl_no_verify_callback);
+#if (OPENSSL_VERSION_NUMBER >= 0x10100000L)
   // Limit to TLS 1.2 for now. TLS 1.3 has broken the handshake code.
   SSL_CTX_set_max_proto_version(ssl_ctx_, TLS1_2_VERSION);
+#endif
 #if DEBUG_SSL
   SSL_CTX_set_info_callback(ssl_ctx_, ssl_info_callback);
 #endif