Merge branch 'jk/unused-anno-more'

More UNUSED annotation to help using -Wunused option with the compiler. * jk/unused-anno-more: ll-merge: mark unused parameters in callbacks diffcore-pickaxe: mark unused parameters in pickaxe functions convert: mark unused parameter in null stream filter apply: mark unused parameters in noop error/warning routine apply: mark unused parameters in handlers date: mark unused parameters in handler functions string-list: mark unused callback parameters object-file: mark unused parameters in hash_unknown functions mark unused parameters in trivial compat functions update-index: drop unused argc from do_reupdate() submodule--helper: drop unused argc from module_list_compute() diffstat_consume(): assert non-zero length