krb5_build_principal and krb5_build_principal_va perform
the same function; the former takes variadic arguments, while the
latter takes a pre-computed varargs pointer.Both functions take
a realm name realm, realm name length rlen,
and a list of null-terminated strings, and fill in a pointer to
a principal structure princ, making it
point to a structure representing the named principal. The last
string must be followed in the argument list by a null pointer.