--- a/main.c
+++ b/main.c
@@ -26,6 +26,8 @@
  * $Id: ipcad-3.7.3-signal_h.patch,v 1.3 2014/07/12 17:45:38 jer Exp $
  */
 
+#include <signal.h> /* signal */
+
 #include "ipcad.h"
 #include "cfgvar.h"
 #include "servers.h"
--- a/pps.c
+++ b/pps.c
@@ -26,6 +26,7 @@
  * $Id: ipcad-3.7.3-signal_h.patch,v 1.3 2014/07/12 17:45:38 jer Exp $
  */
 
+#include <signal.h> /* sigprocmask */
 
 #include "ipcad.h"
 #include "opt.h"
--- a/servers.c
+++ b/servers.c
@@ -26,6 +26,8 @@
  * $Id: ipcad-3.7.3-signal_h.patch,v 1.3 2014/07/12 17:45:38 jer Exp $
  */
 
+#include <signal.h> /* pthread_kill and sigprocmask */
+
 #include "ipcad.h"
 #include "servers.h"
 #include "opt.h"