diff --git a/watchdog.c b/watchdog.c
index fed9f4f9..b2d779ce 100644
--- a/watchdog.c
+++ b/watchdog.c
@@ -22,6 +22,7 @@
  */
 
 #include <paths.h>
+#include <signal.h>
 #include <sys/un.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>