--- qt-everywhere-src-6.9.3.old/qtquick3d/src/3rdparty/xatlas/xatlas.cpp
+++ qt-everywhere-src-6.9.3/qtquick3d/src/3rdparty/xatlas/xatlas.cpp
@@ -52,6 +52,7 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
+#include <cstdlib>
 
 #ifndef XA_DEBUG
 #ifdef NDEBUG