diff --git a/mach/m68020/ncg/mach.h b/mach/m68020/ncg/mach.h
index 5f741640e..c9c975a3e 100644
--- a/mach/m68020/ncg/mach.h
+++ b/mach/m68020/ncg/mach.h
@@ -3,7 +3,7 @@
  * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
  * See the copyright notice in the ACK home directory, in the file "Copyright".
  */
-#include "whichone.h"
+#include <whichone.h>
 
 #ifndef TBL68020
 #ifndef TBL68000
diff --git a/mach/m68k2/ncg/mach.h b/mach/m68k2/ncg/mach.h
index 5f741640e..c9c975a3e 100644
--- a/mach/m68k2/ncg/mach.h
+++ b/mach/m68k2/ncg/mach.h
@@ -3,7 +3,7 @@
  * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
  * See the copyright notice in the ACK home directory, in the file "Copyright".
  */
-#include "whichone.h"
+#include <whichone.h>
 
 #ifndef TBL68020
 #ifndef TBL68000
diff --git a/mach/m68k4/ncg/mach.h b/mach/m68k4/ncg/mach.h
index 5f741640e..c9c975a3e 100644
--- a/mach/m68k4/ncg/mach.h
+++ b/mach/m68k4/ncg/mach.h
@@ -3,7 +3,7 @@
  * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
  * See the copyright notice in the ACK home directory, in the file "Copyright".
  */
-#include "whichone.h"
+#include <whichone.h>
 
 #ifndef TBL68020
 #ifndef TBL68000
diff --git a/mach/moon3/ncg/mach.h b/mach/moon3/ncg/mach.h
index 5f741640e..c9c975a3e 100644
--- a/mach/moon3/ncg/mach.h
+++ b/mach/moon3/ncg/mach.h
@@ -3,7 +3,7 @@
  * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
  * See the copyright notice in the ACK home directory, in the file "Copyright".
  */
-#include "whichone.h"
+#include <whichone.h>
 
 #ifndef TBL68020
 #ifndef TBL68000