fn do_thin_lto<'a, B: ExtraBackendMethods>(
cgcx: &'a CodegenContext<B>,
exported_symbols_for_lto: Arc<Vec<String>>,
each_linked_rlib_for_lto: Vec<PathBuf>,
needs_thin_lto: Vec<(String, <B as WriteBackendMethods>::ThinBuffer)>,
lto_import_only_modules: Vec<(SerializedModule<<B as WriteBackendMethods>::ModuleBuffer>, WorkProduct)>,
) -> Vec<CompiledModule>