* All the original code used here was torn by Marc Prud'hommeaux out of the
* Samba project (by Andrew Tridgell, Jeremy Allison, and others).
+ *
+ * Copyright (c) The Exim Maintainers 2021
+ * SPDX-License-Identifier: GPL-2.0-or-later
* Tom Kistner provided additional code, adding spa_build_auth_challenge() to
* support server authentication mode.