diff --git a/include/boost/config/compiler/codegear.hpp b/include/boost/config/compiler/codegear.hpp
index 52531d2f..91f40a92 100644
--- a/include/boost/config/compiler/codegear.hpp
+++ b/include/boost/config/compiler/codegear.hpp
@@ -124,6 +124,7 @@
 #define BOOST_NO_CXX11_REF_QUALIFIERS
 #define BOOST_NO_CXX11_FINAL
 #define BOOST_NO_CXX11_THREAD_LOCAL
+#define BOOST_NO_CXX11_UNRESTRICTED_UNION
 
 // C++ 14:
 #if !defined(__cpp_aggregate_nsdmi) || (__cpp_aggregate_nsdmi < 201304)