--- a/src/user_display.h
+++ b/src/user_display.h
@@ -26,6 +26,7 @@
 #include "datadirs.h"
 #include "input_event_handler.h"
 #include "texture.h" // fixme replace by "gpu_interface.h"
+#include <optional>
 class image;
 class xml_elem;
 
--- a/src/global_data.h
+++ b/src/global_data.h
@@ -28,6 +28,7 @@
 
 #include <cmath>
 #include <iomanip>
+#include <memory>
 #include <list>
 #include <sstream>
 #include <string>