message: Fix binary operator-(builtin::int4)
diff: @@ -171,10 +171,10 @@ MATH_FUNC
  VSNRAY_FORCE_INLINE int4 operator-(int4 const& u, int4 const& v)
  {
  return int4(
  - u.value[0] + v.value[0],
  - u.value[1] + v.value[1],
  - u.value[2] + v.value[2],
  - u.value[3] + v.value[3]
  + u.value[0] - v.value[0],
  + u.value[1] - v.value[1],
  + u.value[2] - v.value[2],
  + u.value[3] - v.value[3]
  );
  }
  