Bug: https://bugs.gentoo.org/910712
Bug: https://gitlab.xfce.org/panel-plugins/xfce4-cpugraph-plugin/-/issues/37

Signed-off-by: Holger Hoffstätte <holger@applied-asynchrony.com>

--- a/xfce4++/util/gtk.cc~	2023-07-22 22:44:01.000000000 +0200
+++ b/xfce4++/util/gtk.cc	2023-07-23 10:01:32.508675676 +0200
@@ -19,6 +19,7 @@
  */
 
 #include "gtk.h"
+#include <cstdint>
 
 namespace xfce4 {