message: Declare vector constructors to be const
  This makes it easier to create vectors in constants.
diff: @@ -99,7 +99,7 @@ macro_rules! impl_vector {
  impl<S> $VectorN<S> {
  /// Construct a new vector, using the provided values.
  #[inline]
  - pub fn new($($field: S),+) -> $VectorN<S> {
  + pub const fn new($($field: S),+) -> $VectorN<S> {
  $VectorN { $($field: $field),+ }
  }
  @@ -115,7 +115,7 @@ macro_rules! impl_vector {
  /// The short constructor.
  #[inline]
  - pub fn $constructor<S>($($field: S),+) -> $VectorN<S> {
  + pub const fn $constructor<S>($($field: S),+) -> $VectorN<S> {
  $VectorN::new($($field),+)
  }
  