Function add_lld_args

fn add_lld_args(
    cmd: &mut dyn Linker,
    sess: &Session,
    flavor: LinkerFlavor,
    self_contained_components: LinkSelfContainedComponents,
)

When using the linker flavors opting in to lld, add the necessary paths and arguments to invoke it:

• when the self-contained linker flag is active: the build of lld distributed with rustc,
• or any lld available to cc.