diff --git a/Quake/mathlib.c b/Quake/mathlib.c
index 5590bebc..c94ef8c5 100644
--- a/Quake/mathlib.c
+++ b/Quake/mathlib.c
@@ -25,7 +25,6 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 #include "quakedef.h"
 
 vec3_t vec3_origin = {0,0,0};
-int nanmask = 255<<23;
 
 /*-----------------------------------------------------------------*/
 
diff --git a/Quake/mathlib.h b/Quake/mathlib.h
index 276ab1d7..a6b8b8b3 100644
--- a/Quake/mathlib.h
+++ b/Quake/mathlib.h
@@ -42,9 +42,9 @@ typedef	int	fixed16_t;
 struct mplane_s;
 
 extern vec3_t vec3_origin;
-extern	int nanmask;
 
-#define	IS_NAN(x) (((*(int *)&x)&nanmask)==nanmask)
+#define	nanmask		(255<<23)	/* 7F800000 */
+#define	IS_NAN(x)	(((*(int *) &x) & nanmask) == nanmask)
 
 #define CLAMP(_minval, x, _maxval) ((x) < (_minval) ? (_minval) : (x) > (_maxval) ? (_maxval) : (x))