diff --git a/src/openssl.h b/src/openssl.h
index f2da003a..4a2b6319 100644
--- a/src/openssl.h
+++ b/src/openssl.h
@@ -99,7 +99,8 @@
 
 #if (OPENSSL_VERSION_NUMBER >= 0x10100000L && \
     !defined(LIBRESSL_VERSION_NUMBER)) || defined(LIBSSH2_WOLFSSL) || \
-    LIBRESSL_VERSION_NUMBER >= 0x3050000fL
+    (defined(LIBRESSL_VERSION_NUMBER) && \
+    LIBRESSL_VERSION_NUMBER >= 0x3050000fL)
 /* For wolfSSL, whether the structs are truly opaque or not, it's best to not
  * rely on their internal data members being exposed publicly. */
 # define HAVE_OPAQUE_STRUCTS 1