P0013R1 Logical type traits

Optional pieces conditional on P0006R0 being applied.

Author: zygoloid

source/utilities.tex

@@ -9316,8 +9316,11 @@
 
   // \ref{meta.logical}, logical operator traits:
   template<class... B> struct conjunction;
+  template<class... B> constexpr bool conjunction_v = conjunction<B...>::value;
   template<class... B> struct disjunction;
+  template<class... B> constexpr bool disjunction_v = disjunction<B...>::value;
   template<class B> struct negation;
+  template<class B> constexpr bool negation_v = negation<B>::value;
 } // namespace std
 \end{codeblock}