Proper behaviour of aggregate functions of Nullable arguments [#CLICKHOUSE-2832].

dbms/include/DB/AggregateFunctions/AggregateFunctionNull.h

@@ -263,7 +263,7 @@ public:
 	}
 
 private:
-	static constexpr size_t MAX_ARGS = 8;
+	enum { MAX_ARGS = 8 };
 	size_t number_of_arguments = 0;
 	std::array<char, MAX_ARGS> is_nullable;	/// Plain array is better than std::vector due to one indirection less.
 };