stunnel license (see COPYRIGHT.GPL for detailed GPL conditions)

Copyright (C) 1998-2018 Michal Trojnara

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, see <http://www.gnu.org/licenses>.

Linking stunnel statically or dynamically with other modules is making
a combined work based on stunnel. Thus, the terms and conditions of the
GNU General Public License cover the whole combination.

In addition, as a special exception, the copyright holder of stunnel gives you
permission to combine stunnel with free software programs or libraries that
are released under the GNU LGPL and with code included in the standard release
of OpenSSL under the OpenSSL License (or modified versions of such code, with
unchanged license). You may copy and distribute such a system following the
terms of the GNU GPL for stunnel and the licenses of the other code concerned.

Note that people who make modified versions of stunnel are not obligated to
grant this special exception for their modified versions; it is their choice
whether to do so. The GNU General Public License gives permission to release
a modified version without this exception; this exception also makes it
possible to release a modified version which carries forward this exception.