Added license exception to explicitly allow linking to OpenSSL (fixes #…

…713)

COPYING

@@ -404,6 +404,14 @@ where to find the applicable terms.
 form of a separately written license, or stated as exceptions;
 the above requirements apply either way.
 
+If you modify this Program, or any covered work, by linking or combining
+it with OpenSSL (or a modified version of that library), containing
+parts covered by the terms of OpenSSL License, the licensors of this
+Program grant you additional permission to convey the resulting work.
+Corresponding Source for a  non-source form of such a combination shall
+include the source code for the parts of openssl used as well as that of
+the covered work.
+
   8. Termination.
 
   You may not propagate or modify a covered work except as expressly