busybox

od: fix -S NUM to not print chars >0x80

function                                             old     new   delta
write_block                                          433     431      -2
print_ascii                                          217     215      -2
check_and_close                                      104      96      -8
od_main                                             2164    2139     -25

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>