diff --git a/thirdparty/clipper2/Clipper2Lib/include/clipper2/clipper.engine.h b/thirdparty/clipper2/Clipper2Lib/include/clipper2/clipper.engine.h
index 306afa1233..887c0e8665 100644
--- a/thirdparty/clipper2/Clipper2Lib/include/clipper2/clipper.engine.h
+++ b/thirdparty/clipper2/Clipper2Lib/include/clipper2/clipper.engine.h
@@ -19,6 +19,10 @@
 #include <functional>
 #include "clipper.core.h"
 
+#ifdef None
+#undef None
+#endif
+
 namespace Clipper2Lib {
 
 	struct Scanline;