diff --git a/mach/m68020/ncg/mach.c b/mach/m68020/ncg/mach.c
index 636a79860..5651cac4f 100644
--- a/mach/m68020/ncg/mach.c
+++ b/mach/m68020/ncg/mach.c
@@ -9,7 +9,7 @@
  * machine dependent back end routines for the Motorola 68000, 68010 or 68020
  */
 
-#include "whichone.h"
+#include <whichone.h>
 #include <stb.h>
 
 con_part(sz,w) register sz; word w; {
diff --git a/mach/m68k2/ncg/mach.c b/mach/m68k2/ncg/mach.c
index 636a79860..5651cac4f 100644
--- a/mach/m68k2/ncg/mach.c
+++ b/mach/m68k2/ncg/mach.c
@@ -9,7 +9,7 @@
  * machine dependent back end routines for the Motorola 68000, 68010 or 68020
  */
 
-#include "whichone.h"
+#include <whichone.h>
 #include <stb.h>
 
 con_part(sz,w) register sz; word w; {
diff --git a/mach/m68k4/ncg/mach.c b/mach/m68k4/ncg/mach.c
index 636a79860..5651cac4f 100644
--- a/mach/m68k4/ncg/mach.c
+++ b/mach/m68k4/ncg/mach.c
@@ -9,7 +9,7 @@
  * machine dependent back end routines for the Motorola 68000, 68010 or 68020
  */
 
-#include "whichone.h"
+#include <whichone.h>
 #include <stb.h>
 
 con_part(sz,w) register sz; word w; {
diff --git a/mach/moon3/ncg/mach.c b/mach/moon3/ncg/mach.c
index 636a79860..5651cac4f 100644
--- a/mach/moon3/ncg/mach.c
+++ b/mach/moon3/ncg/mach.c
@@ -9,7 +9,7 @@
  * machine dependent back end routines for the Motorola 68000, 68010 or 68020
  */
 
-#include "whichone.h"
+#include <whichone.h>
 #include <stb.h>
 
 con_part(sz,w) register sz; word w; {