--- a/timer.c
+++ b/timer.c
@@ -8,6 +8,7 @@
  */
 #include <stdio.h>
 #include <unistd.h>
+#include <stdlib.h> /* exit() */
 #include "hunt.h"
 
 struct list timejob_list = LIST_INIT(struct timejob, j_next);