_krb5_crc_update
crc = _krb5_crc_update(in->value, in->length, 0);
_krb5_crc_update (const char *p, size_t len, uint32_t res);
crc = _krb5_crc_update(message_buffer->value,
crc = _krb5_crc_update (data, len, 0);
_krb5_crc_update (