functional (__is_socketlike): Change from class template to alias template.

	* include/std/functional (__is_socketlike): Change from class
	template to alias template.

From-SVN: r193832

libstdc++-v3/ChangeLog

 2012-11-26  Jonathan Wakely  <jwakely.gcc@gmail.com>
 
+	* include/std/functional (__is_socketlike): Change from class
+	template to alias template.
+
+2012-11-26  Jonathan Wakely  <jwakely.gcc@gmail.com>
+
 	PR libstdc++/55463
 	* include/std/functional (_Mem_fn): Handle rvalue objects. Add
 	noexcept-specifications.

libstdc++-v3/include/std/functional

@@ -1503,14 +1503,8 @@ _GLIBCXX_HAS_NESTED_TYPE(result_type)
   // Trait type used to remove std::bind() from overload set via SFINAE
   // when first argument has integer type, so that std::bind() will
   // not be a better match than ::bind() from the BSD Sockets API.
-  template<typename _Tp>
-    class __is_socketlike
-    {
-      typedef typename decay<_Tp>::type _Tp2;
-    public:
-      static const bool value =
-	is_integral<_Tp2>::value || is_enum<_Tp2>::value;
-    };
+  template<typename _Tp, typename _Tp2 = typename decay<_Tp>::type>
+    using __is_socketlike = __or_<is_integral<_Tp2>, is_enum<_Tp2>>;
 
   template<bool _SocketLike, typename _Func, typename... _BoundArgs>
     struct _Bind_helper