krb5_db_get_s4u_x509_principal
krb5_error_code krb5_db_get_s4u_x509_principal(krb5_context kcontext,
return krb5_db_get_s4u_x509_principal(context, &cert, req->client,
code = krb5_db_get_s4u_x509_principal(context,