diff --git a/timer.c b/timer.c
index 1ede49cd..ede0c36d 100644
--- a/timer.c
+++ b/timer.c
@@ -13,6 +13,7 @@
  *
  */
 
+#include "config.h"
 #include "radvd.h"
 
 struct timeval next_timeval(double next)