diff --git a/extensions/libxt_hashlimit.c b/extensions/libxt_hashlimit.c
index 831345b..c5b8d77 100644
--- a/extensions/libxt_hashlimit.c
+++ b/extensions/libxt_hashlimit.c
@@ -10,6 +10,8 @@
  * 
  * Error corections by nmalykh@bilim.com (22.01.2005)
  */
+#define _BSD_SOURCE 1
+#define _ISOC99_SOURCE 1
 #include <math.h>
 #include <stdbool.h>
 #include <stdint.h>
diff --git a/extensions/libxt_limit.c b/extensions/libxt_limit.c
index 023500c..f75ef2f 100644
--- a/extensions/libxt_limit.c
+++ b/extensions/libxt_limit.c
@@ -3,6 +3,8 @@
  * Jérôme de Vivie   <devivie@info.enserb.u-bordeaux.fr>
  * Hervé Eychenne    <rv@wallfire.org>
  */
+#define _BSD_SOURCE 1
+#define _ISOC99_SOURCE 1
 #include <math.h>
 #include <stdio.h>
 #include <string.h>