Headers: Add a way to select simplified implementation of enable_if

Author: p12tic

headers/type_traits

@@ -368,6 +368,18 @@ template<class T>
 using decay_t = T; // SIMPLIFIED typedef
 #endif
 
+#if CPPREFERENCE_SIMPLIFY_TYPEDEFS
+
+template<bool, class T = void> struct enable_if {
+    typedef int type; // SIMPLIFIED type
+};
+#if CPPREFERENCE_STDVER >= 2014
+template<bool, class T = void>
+using enable_if_t = int; // SIMPLIFIED typedef
+#endif
+
+#else
+
 template<bool, class T = void> struct enable_if {};
 
 template<class T>
@@ -379,6 +391,8 @@ template<bool B, class T = void>
 using enable_if_t = typename enable_if<B, T>::type;
 #endif
 
+#endif // CPPREFERENCE_SIMPLIFY_TYPEDEFS
+
 template<bool, class T, class F> struct conditional {
     typedef int type; // SIMPLIFIED type
 };