diff --git a/sys/pc98/pc98/pc98.c b/sys/pc98/pc98/pc98.c
index 54db431d86a3..12a471395f1f 100644
--- a/sys/pc98/pc98/pc98.c
+++ b/sys/pc98/pc98/pc98.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)isa.c	7.2 (Berkeley) 5/13/91
- *	$Id: pc98.c,v 1.45 1997/12/01 09:37:26 kato Exp $
+ *	$Id: pc98.c,v 1.46 1998/01/31 14:48:52 kato Exp $
  */
 
 /*
@@ -47,6 +47,8 @@
  * isa_dmastart()
  */
 
+#include "opt_diagnostic.h"
+
 /*
  * modified for PC9801 by A.Kojima F.Ukai M.Ishii 
  *			Kyoto University Microcomputer Club (KMC)