sgi.com now forwards to hpe.com, which is technically unrelated to these
links. Let's link to waybackmachine instead.
Signed-off-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>
<h2>1.6 Are there other open-source implementations of OpenGL?</h2>
<p>
-Yes, SGI's <a href="http://oss.sgi.com/projects/ogl-sample/index.html">
+Yes, SGI's <a href="http://web.archive.org/web/20171010115110_/http://oss.sgi.com/projects/ogl-sample/index.html">
OpenGL Sample Implementation (SI)</a> is available.
The SI was written during the time that OpenGL was originally designed.
Unfortunately, development of the SI has stagnated.
<h2>February 16, 1999</h2>
<p><a href="https://www.sgi.com/">SGI</a> releases its
-<a href="https://www.sgi.com/software/opensource/glx/">GLX source code</a>.</p>
+<a href="http://web.archive.org/web/20040805154836/http://www.sgi.com/software/opensource/glx/download.html">GLX source code</a>.
+</p>
<h2>January 22, 1999</h2>
<p><a href="https://www.mesa3d.org">www.mesa3d.org</a> established</p>