Merge branch 'jk/pack-idx-corruption-safety' into maint

The code to read the pack data using the offsets stored in the pack idx file has been made more carefully check the validity of the data in the idx. * jk/pack-idx-corruption-safety: sha1_file.c: mark strings for translation use_pack: handle signed off_t overflow nth_packed_object_offset: bounds-check extended offset t5313: test bounds-checks of corrupted/malicious pack/idx files