GPL version issue

[Gregor Richards]

The code in dmd/src/dmd is licensed as follows:

// License for redistribution is by either the Artistic License
// in artistic.txt, or the GNU General Public License in gnu.txt.

This is problematic because:

1) There is no file named gnu.txt
2) The file gpl.txt includes the ancient GPL v1, and never is it 
explicitly stated that you may use later versions.

(By the way, Walter, do you use Perl? ;) )

This is a problem because it may be implied that you can only release 
the DMD frontend under version 1 one of the license, in which case I'm 
fairly sure that GDC isn't even legal :).  I'm sure the intention was to 
release it under any version of the GPL.

I think the license text should be changed to:

// License for redistribution is by either the Artistic License
// in artistic.txt, or the GNU General Public License; either
// version 1 (included in gpl.txt) or (at your option) any later
// version.


Opinions?

  - Gregor Richards