#[allow(unused_assignments, unused_mut, unused_variables)]
pub const STD: &str = {
    let mut flag = "c++11";

    #[cfg(feature = "c++14")]
    (flag = "c++14");

    #[cfg(feature = "c++17")]
    (flag = "c++17");

    #[cfg(feature = "c++20")]
    (flag = "c++20");

    flag
};