maint: update copyrights across project.

* AUTHORS: Correct manually modified copyright to be consistent with
other files.

9 files changed, 12 insertions, 9 deletions

diff --git a/m4/autobuild.m4 b/m4/autobuild.m4
index 4ae5b2eb..c1e9fbd3 100644
--- a/m4/autobuild.m4
+++ b/m4/autobuild.m4
@@ -1,5 +1,5 @@
 # autobuild.m4 serial 7
-dnl Copyright (C) 2004, 2006-2019 Free Software Foundation, Inc.
+dnl Copyright (C) 2004, 2006-2019, 2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
diff --git a/m4/libtool.m4 b/m4/libtool.m4
index f2d1f398..e4579a76 100644
--- a/m4/libtool.m4
+++ b/m4/libtool.m4
@@ -1,6 +1,7 @@
 # libtool.m4 - Configure libtool for the host system. -*-Autoconf-*-
 #
-#   Copyright (C) 1996-2001, 2003-2019 Free Software Foundation, Inc.
+#   Copyright (C) 1996-2001, 2003-2019, 2021 Free Software Foundation,
+#   Inc.
 #   Written by Gordon Matzigkeit, 1996
 #
 # This file is free software; the Free Software Foundation gives
diff --git a/m4/ltargz.m4 b/m4/ltargz.m4
index 17a440a4..29d9813c 100644
--- a/m4/ltargz.m4
+++ b/m4/ltargz.m4
@@ -1,6 +1,7 @@
 # Portability macros for glibc argz.                    -*- Autoconf -*-
 #
-#   Copyright (C) 2004-2007, 2011-2019 Free Software Foundation, Inc.
+#   Copyright (C) 2004-2007, 2011-2019, 2021 Free Software Foundation,
+#   Inc.
 #   Written by Gary V. Vaughan <gary@gnu.org>
 #
 # This file is free software; the Free Software Foundation gives
diff --git a/m4/ltdl.m4 b/m4/ltdl.m4
index fe96546c..33220bbe 100644
--- a/m4/ltdl.m4
+++ b/m4/ltdl.m4
@@ -1,6 +1,7 @@
 # ltdl.m4 - Configure ltdl for the target system. -*-Autoconf-*-
 #
-#   Copyright (C) 1999-2008, 2011-2019 Free Software Foundation, Inc.
+#   Copyright (C) 1999-2008, 2011-2019, 2021 Free Software Foundation,
+#   Inc.
 #   Written by Thomas Tanner, 1999
 #
 # This file is free software; the Free Software Foundation gives
diff --git a/m4/ltoptions.m4 b/m4/ltoptions.m4
index c1664256..196ff33a 100644
--- a/m4/ltoptions.m4
+++ b/m4/ltoptions.m4
@@ -1,6 +1,6 @@
 # Helper functions for option handling.                    -*- Autoconf -*-
 #
-#   Copyright (C) 2004-2005, 2007-2009, 2011-2019 Free Software
+#   Copyright (C) 2004-2005, 2007-2009, 2011-2019, 2021 Free Software
 #   Foundation, Inc.
 #   Written by Gary V. Vaughan, 2004
 #
diff --git a/m4/ltsugar.m4 b/m4/ltsugar.m4
index e652d5a1..665af38d 100644
--- a/m4/ltsugar.m4
+++ b/m4/ltsugar.m4
@@ -1,6 +1,6 @@
 # ltsugar.m4 -- libtool m4 base layer.                         -*-Autoconf-*-
 #
-# Copyright (C) 2004-2005, 2007-2008, 2011-2019 Free Software
+# Copyright (C) 2004-2005, 2007-2008, 2011-2019, 2021 Free Software
 # Foundation, Inc.
 # Written by Gary V. Vaughan, 2004
 #
diff --git a/m4/ltversion.in b/m4/ltversion.in
index 953b0d78..6b1a9600 100644
--- a/m4/ltversion.in
+++ b/m4/ltversion.in
@@ -1,6 +1,6 @@
 # ltversion.m4 -- version numbers			-*- Autoconf -*-
 #
-#   Copyright (C) 2004, 2011-2019 Free Software Foundation, Inc.
+#   Copyright (C) 2004, 2011-2019, 2021 Free Software Foundation, Inc.
 #   Written by Scott James Remnant, 2004
 #
 # This file is free software; the Free Software Foundation gives
diff --git a/m4/lt~obsolete.m4 b/m4/lt~obsolete.m4
index 6c846b8f..cb15d089 100644
--- a/m4/lt~obsolete.m4
+++ b/m4/lt~obsolete.m4
@@ -1,6 +1,6 @@
 # lt~obsolete.m4 -- aclocal satisfying obsolete definitions.    -*-Autoconf-*-
 #
-#   Copyright (C) 2004-2005, 2007, 2009, 2011-2019 Free Software
+#   Copyright (C) 2004-2005, 2007, 2009, 2011-2019, 2021 Free Software
 #   Foundation, Inc.
 #   Written by Scott James Remnant, 2004.
 #
diff --git a/m4/m4.m4 b/m4/m4.m4
index f284ecb4..75998e91 100644
--- a/m4/m4.m4
+++ b/m4/m4.m4
@@ -1,6 +1,6 @@
 # m4.m4 serial 12
 
-# Copyright (C) 2000, 2006-2019 Free Software Foundation, Inc.
+# Copyright (C) 2000, 2006-2019, 2021 Free Software Foundation, Inc.
 
 # Copying and distribution of this file, with or without modification,
 # are permitted in any medium without royalty provided the copyright