diff --git a/tools/qfbsp/include/brush.h b/tools/qfbsp/include/brush.h
index bfdd2e625..11758f678 100644
--- a/tools/qfbsp/include/brush.h
+++ b/tools/qfbsp/include/brush.h
@@ -48,7 +48,7 @@ extern	int			numbrushplanes;
 extern	plane_t		planes[MAX_MAP_PLANES];
 
 brushset_t *Brush_LoadEntity (entity_t *ent, int hullnum);
-int	PlaneTypeForNormal (vec3_t normal);
+int	PlaneTypeForNormal (const vec3_t normal);
 int	FindPlane (plane_t *dplane, int *side);
 
 #endif//qfbsp_brush_h
diff --git a/tools/qfbsp/source/brush.c b/tools/qfbsp/source/brush.c
index a3347af5a..6f8986182 100644
--- a/tools/qfbsp/source/brush.c
+++ b/tools/qfbsp/source/brush.c
@@ -134,7 +134,7 @@ AddToBounds (brushset_t *bs, vec3_t v)
 }
 
 int
-PlaneTypeForNormal (vec3_t normal)
+PlaneTypeForNormal (const vec3_t normal)
 {
 	float	ax, ay, az;