Work around missing braces in init warning

llvm-svn: 329474
diff --git a/libcxx/include/compare b/libcxx/include/compare
index 2aa4d86..fd4d7f5 100644
--- a/libcxx/include/compare
+++ b/libcxx/include/compare
@@ -635,7 +635,7 @@
 template <class ..._Ts>
 constexpr auto __get_comp_type() {
   using _CCC = _ClassifyCompCategory;
-  constexpr array<_CCC, sizeof...(_Ts)> __type_kinds{__comp_detail::__type_to_enum<_Ts>()...};
+  constexpr array<_CCC, sizeof...(_Ts)> __type_kinds{{__comp_detail::__type_to_enum<_Ts>()...}};
   constexpr _CCC _Cat = sizeof...(_Ts) == 0 ? _StrongOrd
       : __compute_comp_type(__type_kinds);
   if constexpr (_Cat == _None)