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 (a copy is included as `LICENSE.GPLv2`), or (at your option) any later version. As a special exception, the copyright holders of this library give you permission to link this library with the independent modules that constitute the package and its dependencies for the purpose of producing the `cabal` executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting `cabal` executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obliged to do so. If you do not wish to do so, delete this exception statement from your version. The aforementioned special exception applies (at your option) retroactively to all prior releases of this library.