diff --git a/hw/xfree86/os-support/bsd/alpha_video.c b/hw/xfree86/os-support/bsd/alpha_video.c
index 279391e42..3d1d92467 100644
--- a/hw/xfree86/os-support/bsd/alpha_video.c
+++ b/hw/xfree86/os-support/bsd/alpha_video.c
@@ -42,6 +42,8 @@
 #include "xf86_os_support.h"
 #include "xf86_OSlib.h"
 
+#define DEV_MEM "/dev/mem"
+
 #if defined(__NetBSD__) && !defined(MAP_FILE)
 #define MAP_FLAGS MAP_SHARED
 #else
diff --git a/hw/xfree86/os-support/bsd/arm_video.c b/hw/xfree86/os-support/bsd/arm_video.c
index 15b12a86f..b3da3b2ba 100644
--- a/hw/xfree86/os-support/bsd/arm_video.c
+++ b/hw/xfree86/os-support/bsd/arm_video.c
@@ -70,6 +70,8 @@
 #include "xf86_OSlib.h"
 #include "compiler.h"
 
+#define DEV_MEM "/dev/mem"
+
 #if defined(__NetBSD__) && !defined(MAP_FILE)
 #define MAP_FLAGS MAP_SHARED
 #else
diff --git a/hw/xfree86/os-support/bsd/i386_video.c b/hw/xfree86/os-support/bsd/i386_video.c
index 607e4ca2b..ef64a61ed 100644
--- a/hw/xfree86/os-support/bsd/i386_video.c
+++ b/hw/xfree86/os-support/bsd/i386_video.c
@@ -40,6 +40,8 @@
 #include <machine/sysarch.h>
 #endif
 
+#define DEV_MEM "/dev/mem"
+
 #if defined(__NetBSD__) && !defined(MAP_FILE)
 #define MAP_FLAGS MAP_SHARED
 #else
diff --git a/hw/xfree86/os-support/xf86_OSlib.h b/hw/xfree86/os-support/xf86_OSlib.h
index f973ace86..582d5a9d8 100644
--- a/hw/xfree86/os-support/xf86_OSlib.h
+++ b/hw/xfree86/os-support/xf86_OSlib.h
@@ -230,10 +230,6 @@ struct pcvtid {
 
 #include <limits.h>
 
-#ifndef DEV_MEM
-#define DEV_MEM "/dev/mem"
-#endif
-
 #ifndef MAP_FAILED
 #define MAP_FAILED ((void *)-1)
 #endif