bintimesub
bintimesub(bt, &tk->tk_naptime, bt);
bintimesub(bt, &th->th_naptime, bt);
bintimesub(&th->th_offset, &th->th_naptime, bt);
bintimesub(&utc, &uptime, &boottime);
bintimesub(&utc, &timehands->th_boottime, &uptime);
bintimesub(&new_naptime, &old_naptime, &elapsed);
bintimesub(new_offset, &th->th_offset, &bt);
bintimesub(&th->th_offset, &th->th_naptime,
bintimesub(&th->th_offset, &th->th_naptime, &bt);