Macro tool_rustc_extended

macro_rules! tool_rustc_extended {
    (
        $name:ident {
            path: $path:expr,
            tool_name: $tool_name:expr,
            stable: $stable:expr
            $( , add_bins_to_sysroot: $add_bins_to_sysroot:expr )?
            $( , add_features: $add_features:expr )?
            $( , cargo_args: $cargo_args:expr )?
            $( , )?
        }
    ) => { ... };
}

Creates a step that builds an extended Mode::ToolRustcPrivate tool and installs it into the sysroot of a corresponding compiler.