--- cpp-driver-2.9.0/src/ssl/ssl_openssl_impl.cpp.orig
+++ cpp-driver-2.9.0/src/ssl/ssl_openssl_impl.cpp
@@ -113,7 +113,7 @@
   return len;
 }
 
-#if OPENSSL_VERSION_NUMBER < 0x10100000L
+#if OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER)
 static uv_rwlock_t* crypto_locks;
 
 static void crypto_locking_callback(int mode, int n, const char* file, int line) {
@@ -597,7 +597,7 @@
   SSL_load_error_strings();
   OpenSSL_add_all_algorithms();
 
-#if OPENSSL_VERSION_NUMBER < 0x10100000L
+#if OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER)
   // We have to set the lock/id callbacks for use of OpenSSL thread safety.
   // It's not clear what's thread-safe in OpenSSL. Writing/Reading to
   // a single "SSL" object is NOT and we don't do that, but we do create multiple