Fix absl::container on VS2017 v15.8 (#192)

absl/container/internal/raw_hash_map.h

@@ -39,11 +39,14 @@ class raw_hash_map : public raw_hash_set<Policy, Hash, Eq, Alloc> {
   using MappedConstReference = decltype(P::value(
       std::addressof(std::declval<typename raw_hash_map::const_reference>())));
 
+  using KeyArgImpl = container_internal::KeyArg<IsTransparent<Eq>::value &&
+                                                IsTransparent<Hash>::value>;
+
  public:
   using key_type = typename Policy::key_type;
   using mapped_type = typename Policy::mapped_type;
-  template <typename K>
-  using key_arg = typename raw_hash_map::raw_hash_set::template key_arg<K>;
+  template <class K>
+  using key_arg = typename KeyArgImpl::template type<K, key_type>;
 
   static_assert(!std::is_reference<key_type>::value, "");
   // TODO(alkis): remove this assertion and verify that reference mapped_type is