Macro install

macro_rules! install {
    (($sel:ident, $builder:ident, $_config:ident),
       $($name:ident,
       $condition_name: ident = $path_or_alias: literal,
       $default_cond:expr,
       IS_HOST: $IS_HOST:expr,
       $run_item:block $(, $c:ident)*;)+) => { ... };
}