diff --git a/src/warc.c b/src/warc.c
index 2f1873e2..ea3ad11f 100644
--- a/src/warc.c
+++ b/src/warc.c
@@ -27,10 +27,6 @@ Corresponding Source for a non-source form of such a combination
 shall include the source code for the parts of OpenSSL used as well
 as that of the covered work.  */
 
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#endif
-
 #include "wget.h"
 #include "hash.h"
 #include "utils.h"