diff --git a/src/systty.h b/src/systty.h
index 32941411ee9..3c9a731b9cd 100644
--- a/src/systty.h
+++ b/src/systty.h
@@ -26,6 +26,7 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
 #ifdef HAVE_TERMIOS
 #include <termio.h>
 #include <termios.h>
+#include <fcntl.h>
 #else /* neither HAVE_TERMIO nor HAVE_TERMIOS */
 #ifndef VMS
 #include <sgtty.h>