corrected the compiler workarounds

test/optional_test_convert_from_T.cpp

@@ -41,9 +41,11 @@ struct superconv
 
 void test_optional_of_superconverting_T() // compile-time test
 {
+#ifndef BOOST_OPTIONAL_DETAIL_NO_IS_CONSTRUCTIBLE_TRAIT
   superconv<optional<int> > s;
    superconv<optional<int> > & rs = s;
   optional<superconv<optional<int> > > os = rs;
+#endif
 }
 
 void test_optional_optional_T()