Macro construct_uint

macro_rules! construct_uint {
    ( $(#[$attr:meta])* $visibility:vis struct $name:ident (1); ) => { ... };
    ( $(#[$attr:meta])* $visibility:vis struct $name:ident ( $n_words:tt ); ) => { ... };
    ( @construct $(#[$attr:meta])* $visibility:vis struct $name:ident ( $n_words:tt ); ) => { ... };
}