Function build_extended_rustc_tool

fn build_extended_rustc_tool(
    builder: &Builder<'_>,
    compilers: RustcPrivateCompilers,
    tool_name: &'static str,
    path: &'static str,
    add_bins_to_sysroot: Option<&[&str]>,
    add_features: Option<fn(&Builder<'_>, TargetSelection, &mut Vec<String>)>,
    cargo_args: Option<&[&'static str]>,
) -> ToolBuildResult