diff --git a/convert-objects.c b/convert-objects.c
index ebea8e472b..168771ed85 100644
--- a/convert-objects.c
+++ b/convert-objects.c
@@ -1,5 +1,6 @@
 #define _XOPEN_SOURCE 500 /* glibc2 and AIX 5.3L need this */
 #define _XOPEN_SOURCE_EXTENDED 1 /* AIX 5.3L needs this */
+#define _GNU_SOURCE
 #include <time.h>
 #include "cache.h"
 #include "blob.h"