diff --git a/m4/.gitignore b/m4/.gitignore
index de872f6..f5f6d30 100644
--- a/m4/.gitignore
+++ b/m4/.gitignore
@@ -1,5 +1,6 @@
 /00gnulib.m4
 /absolute-header.m4
+/asm-underscore.m4
 /assert.m4
 /btowc.m4
 /builtin-expect.m4
@@ -18,6 +19,7 @@
 /gnulib-comp.m4
 /gnulib-tool.m4
 /hard-locale.m4
+/host-cpu-c-abi.m4
 /iconv.m4
 /iconv_h.m4
 /iconv_open.m4
diff --git a/m4/gnulib-cache.m4 b/m4/gnulib-cache.m4
index d28c84d..045a4cc 100644
--- a/m4/gnulib-cache.m4
+++ b/m4/gnulib-cache.m4
@@ -1,4 +1,4 @@
-# Copyright (C) 2002-2017 Free Software Foundation, Inc.
+# Copyright (C) 2002-2018 Free Software Foundation, Inc.
 #
 # This file is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -11,7 +11,7 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
-# along with this file.  If not, see <http://www.gnu.org/licenses/>.
+# along with this file.  If not, see <https://www.gnu.org/licenses/>.
 #
 # As a special exception to the GNU General Public License,
 # this file may be distributed as part of a program that