Utility: Fix #6570

[SVN r77699]

include/boost/utility/declval.hpp

@@ -13,6 +13,7 @@
 //----------------------------------------------------------------------------//
 
 #include <boost/type_traits/add_rvalue_reference.hpp>
+//#include <boost/type_traits/add_lvalue_reference.hpp>
 
 //----------------------------------------------------------------------------//
 //                                                                            //
@@ -36,9 +37,13 @@
 
 namespace boost {
 
+//#if !defined(BOOST_NO_RVALUE_REFERENCES)
     template <typename T>
-    typename add_rvalue_reference<T>::type declval(); //noexcept; // as unevaluated operand
-
+    typename add_rvalue_reference<T>::type declval() BOOST_NOEXCEPT; // as unevaluated operand
+//#else
+//    template <typename T>
+//    typename add_lvalue_reference<T>::type declval() BOOST_NOEXCEPT; // as unevaluated operand
+//#endif
 }  // namespace boost
 
 #endif  // BOOST_TYPE_TRAITS_EXT_DECLVAL__HPP