diff --git a/types/data_device/wlr_data_offer.c b/types/data_device/wlr_data_offer.c
index c8fb9b3b..9847e07c 100644
--- a/types/data_device/wlr_data_offer.c
+++ b/types/data_device/wlr_data_offer.c
@@ -1,3 +1,4 @@
+#define _XOPEN_SOURCE 700
 #include <assert.h>
 #include <stdlib.h>
 #include <strings.h>