experimental optional config test

include/boost/optional/detail/optional_config.hpp

@@ -52,4 +52,11 @@
 # define BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS
 #endif
 
+#if (defined(_MSC_VER) && _MSC_VER <= 1800)
+// on MSCV 2013 and earlier an unwanted temporary is created when you assign from
+// a const lvalue of integral type. Thus we bind not to the original address but
+// to a temporary. 
+# define BOOST_OPTIONAL_CONFIG_NO_PROPER_ASSIGN_FROM_CONST_INT
+#endif
+
 #endif // header guard