Revert "Remove examples from gpl.html. Closes #7749."

The GPL folks are a bit overzealous. See https://www.gnu.org/licenses/gpl-faq.html#GPLOmitPreamble

This reverts commit 5cf4f00824e142c8c984099bdf802e6a4b17808b.

src/gui/gpl.html

@@ -426,6 +426,92 @@ PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
 POSSIBILITY OF SUCH DAMAGES.
 </p> 
  
-<h3>END OF TERMS AND CONDITIONS</h3>
+<h3>END OF TERMS AND CONDITIONS</h3> 
+ 
+<h3><a name="howto"></a><a name="SEC4" href="#TOC4">How to Apply These Terms to Your New Programs</a></h3> 
+ 
+<p> 
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+</p> 
+ 
+<p> 
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+</p> 
+ 
+<pre> 
+<var>one line to give the program's name and an idea of what it does.</var> 
+Copyright (C) <var>yyyy</var>  <var>name of author</var> 
+ 
+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, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 
+MA  02110-1301, USA.
+</pre> 
+ 
+<p> 
+Also add information on how to contact you by electronic and paper mail.
+</p> 
+ 
+<p> 
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+</p> 
+ 
+<pre> 
+Gnomovision version 69, Copyright (C) <var>year</var> <var>name of author</var> 
+Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
+type `show w'.  This is free software, and you are welcome
+to redistribute it under certain conditions; type `show c' 
+for details.
+</pre> 
+ 
+<p> 
+The hypothetical commands <samp>`show w'</samp> and <samp>`show c'</samp> should show
+the appropriate parts of the General Public License.  Of course, the
+commands you use may be called something other than <samp>`show w'</samp> and
+<samp>`show c'</samp>; they could even be mouse-clicks or menu items--whatever
+suits your program.
+</p> 
+ 
+<p> 
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary.  Here is a sample; alter the names:
+</p> 
+ 
+ 
+<pre> 
+Yoyodyne, Inc., hereby disclaims all copyright
+interest in the program `Gnomovision'
+(which makes passes at compilers) written 
+by James Hacker.
+ 
+<var>signature of Ty Coon</var>, 1 April 1989
+Ty Coon, President of Vice
+</pre> 
+ 
+<p> 
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the 
+<a href="https://www.gnu.org/licenses/lgpl.html">GNU Lesser General Public License</a> 
+instead of this License.
+</p>
 </body>
 </html>