Make krb5int_check_clockskew() public?

[Linus Nordberg]

Hi,

I'd like krb5int_check_clockskew() to be made public in order to not
have to peek into the krb5_context for clockskew.

The OTP plugin does this today, checking both sec and usec:

--8<---------------cut here---------------start------------->8---
ts_sec = ntohl(*((uint32_t *) (decrypted_data.data + armor_key->length)));
ts_usec = ntohl(*((uint32_t *) (decrypted_data.data + armor_key->length + 4)));
if (labs(now_sec - ts_sec) > context->clockskew
    || (labs(now_sec - ts_sec) == context->clockskew
        && ((now_sec > ts_sec && now_usec > ts_usec)
            || (now_sec < ts_sec && now_usec < ts_usec)))) {
    SERVER_DEBUG("Bad timestamp in PA-OTP-ENC-REQUEST.");
    retval = KRB5KRB_AP_ERR_SKEW;
    goto errout;
}
--8<---------------cut here---------------end--------------->8---

If y'all think usec is important enough, I'd like to see a variant of
krb5int_check_clockskew() taking usec into account as well.

Thanks,
Linus