diff --git a/src/dispnew.c b/src/dispnew.c
index 2b94929ea83..72e7c80f334 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -40,6 +40,7 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
 #include "intervals.h"
 
 #include "systty.h"
+#include "syssignal.h"
 
 #ifdef HAVE_X_WINDOWS
 #include "xterm.h"