macro_rules! tool_extended {
    (($sel:ident, $builder:ident),
       $($name:ident,
       $path:expr,
       $tool_name:expr,
       stable = $stable:expr
       $(,tool_std = $tool_std:literal)?
       $(,allow_features = $allow_features:expr)?
       $(,add_bins_to_sysroot = $add_bins_to_sysroot:expr)?
       ;)+) => { ... };
}