diff --git a/src/tools/qmap.h b/src/tools/qmap.h
index 2c4eb03..4f9772f 100644
--- a/src/tools/qmap.h
+++ b/src/tools/qmap.h
@@ -52,6 +52,7 @@
 #ifndef QT_NO_STL
 #include <iterator>
 #include <map>
+#include <cstddef>
 #endif
 
 //#define QT_CHECK_MAP_RANGE
diff --git a/src/tools/qvaluelist.h b/src/tools/qvaluelist.h
index cf7248e..95dc7ff 100644
--- a/src/tools/qvaluelist.h
+++ b/src/tools/qvaluelist.h
@@ -50,6 +50,7 @@
 #ifndef QT_NO_STL
 #include <iterator>
 #include <list>
+#include <cstddef>
 #endif
 
 //#define QT_CHECK_VALUELIST_RANGE