diff --git a/AUTHORS b/AUTHORS
index fd6da11..e5c8b97 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -33,7 +33,7 @@ Patrick D'Cruze
 Eli Zaretskii
 
 
-Copyright (C) 2001, 2006, 2009-2013, 2015-2019 Free Software Foundation, Inc.
+Copyright (C) 2001, 2006, 2009-2013, 2015-2020 Free Software Foundation, Inc.
 
 This file is part of GNU diffutils.
 
diff --git a/ChangeLog-2008 b/ChangeLog-2008
index de78b44..bc227e2 100644
--- a/ChangeLog-2008
+++ b/ChangeLog-2008
@@ -4265,7 +4265,7 @@ Thu Nov  3 16:30:24 1988  Randall Smith  (randy at gluteus.ai.mit.edu)
 
 	-----
 
-	Copyright (C) 1988-1994, 1997-2002, 2004, 2006, 2009-2013, 2015-2019
+	Copyright (C) 1988-1994, 1997-2002, 2004, 2006, 2009-2013, 2015-2020
 	Free Software Foundation, Inc.
 
 	Copying and distribution of this file, with or without
diff --git a/HACKING b/HACKING
index a012e47..0c60016 100644
--- a/HACKING
+++ b/HACKING
@@ -581,7 +581,7 @@ Then just open the index.html file (in the generated lcov-html directory)
 in your favorite web browser.
 
 ========================================================================
-Copyright (C) 2009-2013, 2015-2019 Free Software Foundation, Inc.
+Copyright (C) 2009-2013, 2015-2020 Free Software Foundation, Inc.
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
diff --git a/Makefile.am b/Makefile.am
index 85fdd00..062649e 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,6 +1,6 @@
 # Main Automakefile for GNU diffutils.
 
-# Copyright (C) 2001-2002, 2004, 2006, 2009-2013, 2015-2019 Free Software
+# Copyright (C) 2001-2002, 2004, 2006, 2009-2013, 2015-2020 Free Software
 # Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/NEWS b/NEWS
index 3ecd111..7295d78 100644
--- a/NEWS
+++ b/NEWS
@@ -442,7 +442,7 @@ User-visible changes in version 2.0:
 
 
 
-Copyright (C) 1993-1994, 1998, 2001-2002, 2004, 2006, 2009-2013, 2015-2019 Free
+Copyright (C) 1993-1994, 1998, 2001-2002, 2004, 2006, 2009-2013, 2015-2020 Free
 Software Foundation, Inc.
 
 This file is part of GNU Diffutils.
diff --git a/README b/README
index a3ba371..e3b0936 100644
--- a/README
+++ b/README
@@ -51,7 +51,7 @@ Please report bugs to <bug-diffutils@gnu.org>.
 
 -----
 
-Copyright (C) 1992, 1998, 2001-2002, 2004, 2009-2013, 2015-2019 Free Software
+Copyright (C) 1992, 1998, 2001-2002, 2004, 2009-2013, 2015-2020 Free Software
 Foundation, Inc.
 
 This file is part of GNU Diffutils.
diff --git a/README-hacking b/README-hacking
index bce61f1..814bccd 100644
--- a/README-hacking
+++ b/README-hacking
@@ -94,7 +94,7 @@ each program.  One way to do this is to use vc-dwim
 
 -----
 
-Copyright (C) 2002-2007, 2009-2013, 2015-2019 Free Software Foundation, Inc.
+Copyright (C) 2002-2007, 2009-2013, 2015-2020 Free Software Foundation, Inc.
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
diff --git a/bootstrap b/bootstrap
index e273ea7..70fd73c 100755
--- a/bootstrap
+++ b/bootstrap
@@ -4,7 +4,7 @@ scriptversion=2019-01-04.17; # UTC
 
 # Bootstrap this package from checked-out sources.
 
-# Copyright (C) 2003-2019 Free Software Foundation, Inc.
+# Copyright (C) 2003-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/bootstrap.conf b/bootstrap.conf
index 1b27c23..c5d2061 100644
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -1,6 +1,6 @@
 # Bootstrap configuration.
 
-# Copyright (C) 2006-2013, 2015-2019 Free Software Foundation, Inc.
+# Copyright (C) 2006-2013, 2015-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/cfg.mk b/cfg.mk
index 6962703..7a272c8 100644
--- a/cfg.mk
+++ b/cfg.mk
@@ -1,5 +1,5 @@
 # Customize maint.mk                           -*- makefile -*-
-# Copyright (C) 2003-2013, 2015-2019 Free Software Foundation, Inc.
+# Copyright (C) 2003-2013, 2015-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/configure.ac b/configure.ac
index 1d61fb4..8194d1f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,6 +1,6 @@
 # Configure template for GNU Diffutils.
 
-# Copyright (C) 1994-1995, 1998, 2001-2002, 2004, 2006, 2009-2013, 2015-2019
+# Copyright (C) 1994-1995, 1998, 2001-2002, 2004, 2006, 2009-2013, 2015-2020
 # Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/doc/Makefile.am b/doc/Makefile.am
index 3b4c724..96a62ad 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -1,6 +1,6 @@
 # Makefile for GNU diffutils documentation.
 
-# Copyright (C) 2001-2002, 2009-2013, 2015-2019 Free Software Foundation, Inc.
+# Copyright (C) 2001-2002, 2009-2013, 2015-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/doc/diffutils.texi b/doc/diffutils.texi
index 3a780db..2f3d412 100644
--- a/doc/diffutils.texi
+++ b/doc/diffutils.texi
@@ -14,8 +14,8 @@ and documents the GNU @command{diff}, @command{diff3},
 differences between files and the GNU @command{patch} command for
 using their output to update files.
 
-Copyright @copyright{} 1992-1994, 1998, 2001-2002, 2004, 2006, 2009-2019 Free
-Software Foundation, Inc.
+Copyright @copyright{} 1992--1994, 1998, 2001--2002, 2004, 2006, 2009--2020
+Free Software Foundation, Inc.
 
 @quotation
 Permission is granted to copy, distribute and/or modify this document
diff --git a/exgettext b/exgettext
index 7c89ca4..1f6a468 100755
--- a/exgettext
+++ b/exgettext
@@ -1,7 +1,7 @@
 #! /bin/sh
 # Wrapper around gettext for programs using the msgid convention.
 
-# Copyright (C) 1998, 2001, 2004, 2009-2013, 2015-2019 Free Software
+# Copyright (C) 1998, 2001, 2004, 2009-2013, 2015-2020 Free Software
 # Foundation, Inc.
 
 # Written by Paul Eggert <eggert@twinsun.com>.
diff --git a/gnulib b/gnulib
index 3f7d8da..86e05ef 160000
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 3f7d8da2ee9e513a9db318dc9c4aa91ca6ed8b3b
+Subproject commit 86e05effe83d629bfcb4d798c4951781387a1bfa
diff --git a/init.cfg b/init.cfg
index d563156..66f8ee9 100644
--- a/init.cfg
+++ b/init.cfg
@@ -1,6 +1,6 @@
 # This file is sourced by init.sh, *before* its initialization.
 
-# Copyright (C) 2010-2019 Free Software Foundation, Inc.
+# Copyright (C) 2010-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 47f7e5f..fbd0909 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -1,6 +1,6 @@
 # Automakefile for GNU Diffutils library.
 
-# Copyright (C) 2001-2002, 2004, 2006, 2009-2013, 2015-2019 Free Software
+# Copyright (C) 2001-2002, 2004, 2006, 2009-2013, 2015-2020 Free Software
 # Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/lib/cmpbuf.c b/lib/cmpbuf.c
index b100a96..ea984c6 100644
--- a/lib/cmpbuf.c
+++ b/lib/cmpbuf.c
@@ -1,6 +1,6 @@
 /* Buffer primitives for comparison operations.
 
-   Copyright (C) 1993, 1995, 1998, 2001-2002, 2006, 2009-2013, 2015-2019 Free
+   Copyright (C) 1993, 1995, 1998, 2001-2002, 2006, 2009-2013, 2015-2020 Free
    Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
diff --git a/lib/cmpbuf.h b/lib/cmpbuf.h
index 9e02d3b..554dd07 100644
--- a/lib/cmpbuf.h
+++ b/lib/cmpbuf.h
@@ -1,6 +1,6 @@
 /* Buffer primitives for comparison operations.
 
-   Copyright (C) 2002, 2009-2013, 2015-2019 Free Software Foundation, Inc.
+   Copyright (C) 2002, 2009-2013, 2015-2020 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
diff --git a/lib/prepargs.c b/lib/prepargs.c
index 4e7af9e..bc33e44 100644
--- a/lib/prepargs.c
+++ b/lib/prepargs.c
@@ -1,6 +1,6 @@
 /* Parse arguments from a string and prepend them to an argv.
 
-   Copyright (C) 1999-2002, 2006, 2009-2013, 2015-2019 Free Software
+   Copyright (C) 1999-2002, 2006, 2009-2013, 2015-2020 Free Software
    Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
diff --git a/man/Makefile.am b/man/Makefile.am
index 88c5623..dfaa883 100644
--- a/man/Makefile.am
+++ b/man/Makefile.am
@@ -1,6 +1,6 @@
 # Automakefile for GNU diffutils man pages
 
-# Copyright (C) 2002, 2009-2013, 2015-2019 Free Software Foundation, Inc.
+# Copyright (C) 2002, 2009-2013, 2015-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/man/help2man b/man/help2man
index 72c00a8..a5709b3 100755
--- a/man/help2man
+++ b/man/help2man
@@ -1,7 +1,7 @@
 #!/usr/bin/perl -w
 
 # Generate a short man page from --help and --version output.
-# Copyright (C) 1997-2005, 2009-2011, 2013, 2015-2019 Free Software Foundation,
+# Copyright (C) 1997-2005, 2009-2011, 2013, 2015-2020 Free Software Foundation,
 # Inc.
 
 # This program is free software; you can redistribute it and/or modify
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 48089c0..3934673 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -1,6 +1,6 @@
 # List of files that contain translatable strings.
 
-# Copyright (C) 2001-2002, 2009-2013, 2015-2019 Free Software Foundation, Inc.
+# Copyright (C) 2001-2002, 2009-2013, 2015-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/po/en.po b/po/en.po
index 3cba889..926edf3 100644
--- a/po/en.po
+++ b/po/en.po
@@ -1,5 +1,5 @@
 # English messages for GNU diffutils
-# Copyright 1998, 2001-2003, 2009-2013, 2015-2019 Free Software Foundation,
+# Copyright 1998, 2001-2003, 2009-2013, 2015-2020 Free Software Foundation,
 # Inc.
 # Paul Eggert <eggert@twinsun.com>, 1998
 #
diff --git a/src/Makefile.am b/src/Makefile.am
index 185b6b3..3ce2433 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,6 +1,6 @@
 # Automakefile for GNU diffutils programs.
 
-# Copyright (C) 2001-2002, 2006, 2009-2013, 2015-2019 Free Software Foundation,
+# Copyright (C) 2001-2002, 2006, 2009-2013, 2015-2020 Free Software Foundation,
 # Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/src/analyze.c b/src/analyze.c
index 642ba81..5693ba3 100644
--- a/src/analyze.c
+++ b/src/analyze.c
@@ -1,7 +1,7 @@
 /* Analyze file differences for GNU DIFF.
 
    Copyright (C) 1988-1989, 1992-1995, 1998, 2001-2002, 2004, 2006-2007,
-   2009-2013, 2015-2019 Free Software Foundation, Inc.
+   2009-2013, 2015-2020 Free Software Foundation, Inc.
 
    This file is part of GNU DIFF.
 
diff --git a/src/cmp.c b/src/cmp.c
index 5152ca0..26b23d9 100644
--- a/src/cmp.c
+++ b/src/cmp.c
@@ -1,7 +1,7 @@
 /* GNU cmp - compare two files byte by byte
 
    Copyright (C) 1990-1996, 1998, 2001-2002, 2004, 2006-2007, 2009-2013,
-   2015-2019 Free Software Foundation, Inc.
+   2015-2020 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
diff --git a/src/context.c b/src/context.c
index cb8e31a..c0bfb4a 100644
--- a/src/context.c
+++ b/src/context.c
@@ -1,7 +1,7 @@
 /* Context-format output routines for GNU DIFF.
 
    Copyright (C) 1988-1989, 1991-1995, 1998, 2001-2002, 2004, 2006, 2009-2013,
-   2015-2019 Free Software Foundation, Inc.
+   2015-2020 Free Software Foundation, Inc.
 
    This file is part of GNU DIFF.
 
diff --git a/src/die.h b/src/die.h
index a542c2a..95f6f0c 100644
--- a/src/die.h
+++ b/src/die.h
@@ -1,5 +1,5 @@
 /* Report an error and exit.
-   Copyright 2016-2019 Free Software Foundation, Inc.
+   Copyright 2016-2020 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
diff --git a/src/diff.c b/src/diff.c
index c545642..00e3013 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -1,7 +1,7 @@
 /* GNU diff - compare files line by line
 
    Copyright (C) 1988-1989, 1992-1994, 1996, 1998, 2001-2002, 2004, 2006-2007,
-   2009-2013, 2015-2019 Free Software Foundation, Inc.
+   2009-2013, 2015-2020 Free Software Foundation, Inc.
 
    This file is part of GNU DIFF.
 
diff --git a/src/diff.h b/src/diff.h
index 5eb3008..767b3be 100644
--- a/src/diff.h
+++ b/src/diff.h
@@ -1,7 +1,7 @@
 /* Shared definitions for GNU DIFF
 
    Copyright (C) 1988-1989, 1991-1995, 1998, 2001-2002, 2004, 2009-2013,
-   2015-2019 Free Software Foundation, Inc.
+   2015-2020 Free Software Foundation, Inc.
 
    This file is part of GNU DIFF.
 
diff --git a/src/diff3.c b/src/diff3.c
index 037df25..bb039a8 100644
--- a/src/diff3.c
+++ b/src/diff3.c
@@ -1,7 +1,7 @@
 /* GNU diff3 - compare three files line by line
 
    Copyright (C) 1988-1989, 1992-1996, 1998, 2001-2002, 2004, 2006, 2009-2013,
-   2015-2019 Free Software Foundation, Inc.
+   2015-2020 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
diff --git a/src/dir.c b/src/dir.c
index b02099a..8aaad17 100644
--- a/src/dir.c
+++ b/src/dir.c
@@ -1,7 +1,7 @@
 /* Read, sort and compare two directories.  Used for GNU DIFF.
 
    Copyright (C) 1988-1989, 1992-1995, 1998, 2001-2002, 2004, 2006-2007,
-   2009-2013, 2015-2019 Free Software Foundation, Inc.
+   2009-2013, 2015-2020 Free Software Foundation, Inc.
 
    This file is part of GNU DIFF.
 
diff --git a/src/ed.c b/src/ed.c
index d9ec83f..3b64208 100644
--- a/src/ed.c
+++ b/src/ed.c
@@ -1,7 +1,7 @@
 /* Output routines for ed-script format.
 
    Copyright (C) 1988-1989, 1991-1993, 1995, 1998, 2001, 2004, 2006, 2009-2013,
-   2015-2019 Free Software Foundation, Inc.
+   2015-2020 Free Software Foundation, Inc.
 
    This file is part of GNU DIFF.
 
diff --git a/src/ifdef.c b/src/ifdef.c
index 43f1f86..601be17 100644
--- a/src/ifdef.c
+++ b/src/ifdef.c
@@ -1,6 +1,6 @@
 /* #ifdef-format output routines for GNU DIFF.
 
-   Copyright (C) 1989, 1991-1994, 2001-2002, 2004, 2006, 2009-2013, 2015-2019
+   Copyright (C) 1989, 1991-1994, 2001-2002, 2004, 2006, 2009-2013, 2015-2020
    Free Software Foundation, Inc.
 
    This file is part of GNU DIFF.
diff --git a/src/io.c b/src/io.c
index 4b126c5..b226081 100644
--- a/src/io.c
+++ b/src/io.c
@@ -1,7 +1,7 @@
 /* File I/O for GNU DIFF.
 
    Copyright (C) 1988-1989, 1992-1995, 1998, 2001-2002, 2004, 2006, 2009-2013,
-   2015-2019 Free Software Foundation, Inc.
+   2015-2020 Free Software Foundation, Inc.
 
    This file is part of GNU DIFF.
 
diff --git a/src/normal.c b/src/normal.c
index 200bfd2..96abd0a 100644
--- a/src/normal.c
+++ b/src/normal.c
@@ -1,6 +1,6 @@
 /* Normal-format output routines for GNU DIFF.
 
-   Copyright (C) 1988-1989, 1993, 1995, 1998, 2001, 2006, 2009-2013, 2015-2019
+   Copyright (C) 1988-1989, 1993, 1995, 1998, 2001, 2006, 2009-2013, 2015-2020
    Free Software Foundation, Inc.
 
    This file is part of GNU DIFF.
diff --git a/src/sdiff.c b/src/sdiff.c
index a61f4e7..1aece14 100644
--- a/src/sdiff.c
+++ b/src/sdiff.c
@@ -1,7 +1,7 @@
 /* GNU sdiff - side-by-side merge of file differences
 
    Copyright (C) 1992-1996, 1998, 2001-2002, 2004, 2006-2007, 2009-2013,
-   2015-2019 Free Software Foundation, Inc.
+   2015-2020 Free Software Foundation, Inc.
 
    This file is part of GNU DIFF.
 
diff --git a/src/side.c b/src/side.c
index 498939d..416dcb4 100644
--- a/src/side.c
+++ b/src/side.c
@@ -1,6 +1,6 @@
 /* sdiff-format output routines for GNU DIFF.
 
-   Copyright (C) 1991-1993, 1998, 2001-2002, 2004, 2009-2013, 2015-2019 Free
+   Copyright (C) 1991-1993, 1998, 2001-2002, 2004, 2009-2013, 2015-2020 Free
    Software Foundation, Inc.
 
    This file is part of GNU DIFF.
diff --git a/src/system.h b/src/system.h
index d032c09..e3c8b1d 100644
--- a/src/system.h
+++ b/src/system.h
@@ -1,7 +1,7 @@
 /* System dependent declarations.
 
    Copyright (C) 1988-1989, 1992-1995, 1998, 2001-2002, 2004, 2006, 2009-2013,
-   2015-2019 Free Software Foundation, Inc.
+   2015-2020 Free Software Foundation, Inc.
 
    This file is part of GNU DIFF.
 
diff --git a/src/util.c b/src/util.c
index 77dd7e2..83897b5 100644
--- a/src/util.c
+++ b/src/util.c
@@ -1,7 +1,7 @@
 /* Support routines for GNU DIFF.
 
    Copyright (C) 1988-1989, 1992-1995, 1998, 2001-2002, 2004, 2006, 2009-2013,
-   2015-2019 Free Software Foundation, Inc.
+   2015-2020 Free Software Foundation, Inc.
 
    This file is part of GNU DIFF.
 
diff --git a/tests/cmp b/tests/cmp
index ff49388..34e195a 100755
--- a/tests/cmp
+++ b/tests/cmp
@@ -1,7 +1,7 @@
 #!/bin/sh
 # Test 'cmp'.
 
-# Copyright 2017-2019 Free Software Foundation, Inc.
+# Copyright 2017-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/envvar-check b/tests/envvar-check
index edcadb2..7e51193 100644
--- a/tests/envvar-check
+++ b/tests/envvar-check
@@ -1,7 +1,7 @@
 # -*- sh -*-
 # Check environment variables for sane values while testing.
 
-# Copyright (C) 2000-2019 Free Software Foundation, Inc.
+# Copyright (C) 2000-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/help-version b/tests/help-version
index dfbf563..2e369a2 100755
--- a/tests/help-version
+++ b/tests/help-version
@@ -2,7 +2,7 @@
 # Make sure all these programs work properly
 # when invoked with --help or --version.
 
-# Copyright (C) 2000-2013, 2015-2019 Free Software Foundation, Inc.
+# Copyright (C) 2000-2013, 2015-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/init.cfg b/tests/init.cfg
index c1f7941..c03b363 100644
--- a/tests/init.cfg
+++ b/tests/init.cfg
@@ -1,6 +1,6 @@
 # This file is sourced by init.sh, *before* its initialization.
 
-# Copyright (C) 2010-2019 Free Software Foundation, Inc.
+# Copyright (C) 2010-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/init.sh b/tests/init.sh
index 8ca5c90..b4a5944 100644
--- a/tests/init.sh
+++ b/tests/init.sh
@@ -1,6 +1,6 @@
 # source this file; set up for tests
 
-# Copyright (C) 2009-2019 Free Software Foundation, Inc.
+# Copyright (C) 2009-2020 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -129,6 +129,8 @@ else
 fi
 
 # We require $(...) support unconditionally.
+# We require that the printf built-in work correctly regarding octal escapes;
+# this eliminates /bin/sh on AIX 7.2.
 # We require non-surprising "local" semantics (this eliminates dash).
 # This takes the admittedly draconian step of eliminating dash, because the
 # assignment tab=$(printf '\t') works fine, yet preceding it with "local "
@@ -158,6 +160,12 @@ fi
 #  ? - not ok
 gl_shell_test_script_='
 test $(echo y) = y || exit 1
+LC_ALL=en_US.UTF-8 printf "\\351" 2>/dev/null \
+  | LC_ALL=C tr "\\351" x | LC_ALL=C grep "^x$" > /dev/null \
+  || exit 1
+printf "\\351" 2>/dev/null \
+  | LC_ALL=C tr "\\351" x | LC_ALL=C grep "^x$" > /dev/null \
+  || exit 1
 f_local_() { local v=1; }; f_local_ || exit 1
 f_dash_local_fail_() { local t=$(printf " 1"); }; f_dash_local_fail_
 score_=10