diff --git a/lib/url.c b/lib/url.c
index 7de06ff3fd..42b7350b0a 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -3599,6 +3599,7 @@ CURLcode Curl_async_resolved(struct connectdata *conn,
   return code;
 #else
   (void)conn;
+  (void)protocol_done;
   return CURLE_OK;
 #endif
 }