Bison Exception

As a special exception, you may create a larger work that contains part or all
of the Bison parser skeleton and distribute that work under terms of your
choice, so long as that work isn't itself a parser generator using the
skeleton or a modified version thereof as a parser skeleton. Alternatively,
if you modify or redistribute the parser skeleton itself, you may (at your
option) remove this special exception, which will cause the skeleton and the
resulting Bison output files to be licensed under the GNU General Public
License without this special exception.

This special exception was added by the Free Software Foundation in version 2.2 of Bison.
