[DotGNU]Small license clarification on pnetlib

[Rhys Weatherley]

I've clarified the license text on pnetlib slightly to be fully consistent 
with GNU Classpath's latest wording for the linking exception:

    As a special exception, the copyright holders of this library give you
    permission to link this library with independent modules to produce an
    executable, regardless of the license terms of these independent modules,
    and to copy and distribute the resulting 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 obligated to do so.  If you do
    not wish to do so, delete this exception statement from your version. 

It is my intention to keep the linking exception synchronized with GNU 
Classpath's from now on so that all similar libraries in the GNU Project use 
consistent licensing.  The original wording was as follows:

    If you link this library against your own program, then you do not need
    to release the source code for that program.  However, any changes that
    you make to the library itself, or to any native methods upon which the
    library relies, must be re-distributed in accordance with the terms of
    the GPL.

The license is otherwise identical to the GPL.

Cheers,

Rhys.