bug#24520: 25.1.50; calccard.tex has somewhat unclear licensing

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > -% Copyright (C) 1987, 1992, 2001-2016 Free Software Foundation, Inc.
  > -
  > -% This file is part of GNU Emacs.
  > -
  > -% GNU Emacs 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 3 of the License, or
  > -% (at your option) any later version.
  > -
  > -% GNU Emacs 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 GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  > -

Don't delete that!  That is the license notice for the source file;
it is required.

    +As a special additional permission, you may distribute reference cards
    +printed, or formatted for printing, with the notice "Released under
    +the terms of the GNU General Public License version 3 or later"
    +instead of the usual distributed-under-the-GNU-GPL notice, and without
    +a copy of the GPL itself.

That is additional permission for using the material in the source
file.  Thus, the right place to add paragraph is INSIDE the license
notice for the source file.  After these two lines.

  > -% the Free Software Foundation, either version 3 of the License, or
  > -% (at your option) any later version.

One other change is needed: to change the TeX code so that
it puts this new notice

   Released under the terms of the GNU General Public License version
   3 or later.

into the output _instead of_ the notice it uses now (which is what
follows):

    Permission is granted to make and distribute copies of
    this card provided the copyright notice and this permission notice
    are preserved on all copies.

-- 
Dr Richard Stallman
President, Free Software Foundation (gnu.org, fsf.org)
Internet Hall-of-Famer (internethalloffame.org)
Skype: No way! See stallman.org/skype.html.