diff --git a/sys/alpha/include/param.h b/sys/alpha/include/param.h
index 8bed4237256d..190b1eb1844a 100644
--- a/sys/alpha/include/param.h
+++ b/sys/alpha/include/param.h
@@ -1,4 +1,4 @@
-/* $Id: param.h,v 1.7 1998/09/09 01:21:25 jdp Exp $ */
+/* $Id: param.h,v 1.8 1999/02/19 19:34:47 luoqi Exp $ */
 /* From: NetBSD: param.h,v 1.20 1997/09/19 13:52:53 leo Exp */
 
 /*
@@ -46,10 +46,18 @@
 /*
  * Machine dependent constants for the Alpha.
  */
+#ifndef _MACHINE
 #define	_MACHINE	alpha
+#endif
+#ifndef MACHINE
 #define	MACHINE		"alpha"
+#endif
+#ifndef _MACHINE_ARCH
 #define	_MACHINE_ARCH	alpha
+#endif
+#ifndef MACHINE_ARCH
 #define	MACHINE_ARCH	"alpha"
+#endif
 #define	MID_MACHINE	MID_ALPHA
 
 #include <machine/alpha_cpu.h>
diff --git a/sys/i386/include/param.h b/sys/i386/include/param.h
index 41034f21dbc3..4f0cbc0d5576 100644
--- a/sys/i386/include/param.h
+++ b/sys/i386/include/param.h
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)param.h	5.8 (Berkeley) 6/28/91
- *	$Id: param.h,v 1.48 1999/01/07 06:35:18 peter Exp $
+ *	$Id: param.h,v 1.49 1999/02/19 19:34:48 luoqi Exp $
  */
 
 #ifndef _MACHINE_PARAM_H_
@@ -43,10 +43,18 @@
 /*
  * Machine dependent constants for Intel 386.
  */
+#ifndef _MACHINE
 #define	_MACHINE	i386
+#endif
+#ifndef MACHINE
 #define MACHINE		"i386"
+#endif
+#ifndef _MACHINE_ARCH
 #define	_MACHINE_ARCH	i386
+#endif
+#ifndef MACHINE_ARCH
 #define	MACHINE_ARCH	"i386"
+#endif
 #define MID_MACHINE	MID_I386
 
 /*