diff --git a/libs/gtkmm2ext/gtkmm2ext/idle_adjustment.h b/libs/gtkmm2ext/gtkmm2ext/idle_adjustment.h
index 00b65f21d8..fdab671759 100644
--- a/libs/gtkmm2ext/gtkmm2ext/idle_adjustment.h
+++ b/libs/gtkmm2ext/gtkmm2ext/idle_adjustment.h
@@ -20,7 +20,9 @@
 #ifndef __gtkmm2ext_idle_adjustment_h__
 #define __gtkmm2ext_idle_adjustment_h__
 
+#include <stdint.h>
 #include <sys/time.h>
+
 #include <gtkmm/adjustment.h>
 
 #include "gtkmm2ext/visibility.h"