fn generate_lto_work<B: ExtraBackendMethods>(
cgcx: &CodegenContext<B>,
needs_fat_lto: Vec<FatLtoInput<B>>,
needs_thin_lto: Vec<(String, B::ThinBuffer)>,
import_only_modules: Vec<(SerializedModule<B::ModuleBuffer>, WorkProduct)>,
) -> Vec<(WorkItem<B>, u64)>