Removed backport of void_t

Author: JohanMabille

include/xsimd/arch/common/xsimd_common_details.hpp

@@ -301,13 +301,11 @@ namespace xsimd
                 using type = with_slow_conversion;
             };
 
-            using xsimd::detail::void_t;
-
             template <class A, class From, class To>
             struct conversion_type_impl<A, From, To,
-                                        void_t<decltype(fast_cast(std::declval<const batch<From, A>&>(),
-                                                                  std::declval<const batch<To, A>&>(),
-                                                                  std::declval<const A&>()))>>
+                                        std::void_t<decltype(fast_cast(std::declval<const batch<From, A>&>(),
+                                                                       std::declval<const batch<To, A>&>(),
+                                                                       std::declval<const A&>()))>>
             {
                 using type = with_fast_conversion;
             };

include/xsimd/memory/xsimd_alignment.hpp

@@ -74,7 +74,7 @@ namespace xsimd
     };
 
     template <class C>
-    struct container_alignment<C, detail::void_t<typename C::allocator_type>>
+    struct container_alignment<C, std::void_t<typename C::allocator_type>>
     {
         using type = allocator_alignment_t<typename C::allocator_type>;
     };

include/xsimd/types/xsimd_api.hpp

@@ -371,7 +371,7 @@ namespace xsimd
         template <class Arch, class Batch, class BatchConstant>
         struct has_bitwise_lshift_batch_const<
             Arch, Batch, BatchConstant,
-            void_t<decltype(kernel::bitwise_lshift<Arch>(
+            std::void_t<decltype(kernel::bitwise_lshift<Arch>(
                 std::declval<Batch>(), std::declval<BatchConstant>(), Arch {}))>>
             : std::true_type
         {

include/xsimd/types/xsimd_utils.hpp

@@ -291,22 +291,6 @@ namespace xsimd
         }
     }
 
-    /*********************************
-     * Backport of void_t from C++17 *
-     *********************************/
-
-    namespace detail
-    {
-        template <class... T>
-        struct make_void
-        {
-            using type = void;
-        };
-
-        template <class... T>
-        using void_t = typename make_void<T...>::type;
-    }
-
     /**************************************************
      * Equivalent of void_t but with size_t parameter *
      **************************************************/