API but not in Heimdal, and add commented out empty versions of
krb5_princ_set_realm_length(), krb5_princ_set_realm_data(),
krb5_princ_name(), and krb5_princ_component(), which also appear
in the MIT API, but which cannot be implemented in Heimdal until
a change is made to how some data is represented internally (as
these API functions expose that, as foolish as that is, but
that's how MIT did it, and some applications use it).
