Update aclocal to 1.16.1 [ci skip]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64920 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

aclocal.m4

@@ -1,6 +1,6 @@
-# generated automatically by aclocal 1.15.1 -*- Autoconf -*-
+# generated automatically by aclocal 1.16.1 -*- Autoconf -*-
 
-# Copyright (C) 1996-2017 Free Software Foundation, Inc.
+# Copyright (C) 1996-2018 Free Software Foundation, Inc.
 
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,