https://bugs.gentoo.org/938230
https://github.com/widelands/widelands/pull/6522
--- a/src/base/format/abstract_node.h
+++ b/src/base/format/abstract_node.h
@@ -21,2 +21,4 @@
 
+#include <cstdint>
+
 namespace format_impl {
--- a/src/logic/map_objects/tribes/training_attribute.h
+++ b/src/logic/map_objects/tribes/training_attribute.h
@@ -21,2 +21,4 @@
 
+#include <cstdint>
+
 namespace Widelands {