File fix-size_t-definition.patch of Package Vrui

--- Vrui/Vislets/FrameRateViewer.h.ori	2021-06-28 15:07:23.271859146 -0400
+++ Vrui/Vislets/FrameRateViewer.h	2021-06-28 15:08:03.366637100 -0400
@@ -26,6 +26,7 @@
 
 #include <GL/GLNumberRenderer.h>
 #include <Vrui/Vislet.h>
+#include <cstddef>
 
 namespace Vrui {