Upgrade link to GPLv2 on gnu.org to https://

diff --git a/doc/source/history.sgml b/doc/source/history.sgml
index 453574c..29d1382 100644 (file)
--- a/doc/source/history.sgml
+++ b/doc/source/history.sgml
@@ -35,7 +35,7 @@
  Junkbuster</application> did not. Version 2.0.2, published in 1998, was
  the last official release, available from Junkbusters Corporation.
  Fortunately, it had been released under the GNU
- <ulink url="http://www.gnu.org/licenses/old-licenses/gpl-2.0.html">GPL</ulink>,
+ <ulink url="https://www.gnu.org/licenses/old-licenses/gpl-2.0.html">GPL</ulink>,
  which allowed further development by others.
 </para>