diff --git a/win32/signal.h b/win32/signal.h
index 484a8d1c002..2058dd873b0 100644
--- a/win32/signal.h
+++ b/win32/signal.h
@@ -3,6 +3,8 @@
 
 #include <signal.h>
 
+#include "win32/winutil.h"
+
 #define SIGALRM 13
 #define	SIGVTALRM 26			/* virtual time alarm */
 #define	SIGPROF	27				/* profiling time alarm */