Attempt to integrate XAD into master

ABOUT-NLS

@@ -110,7 +110,7 @@ people who like their own language and write it well, and who are also
 able to synergize with other translators speaking the same language.
 Each translation team has its own mailing list.  The up-to-date list of
 teams can be found at the Free Translation Project's homepage,
-'https://translationproject.org/', in the "Teams" area.
+'http://translationproject.org/', in the "Teams" area.
 
    If you'd like to volunteer to _work_ at translating messages, you
 should become a member of the translating team for your own language.
@@ -1357,7 +1357,7 @@ mere existence a PO file and its wide availability in a distribution.
    If Jun 2014 seems to be old, you may fetch a more recent copy of this
 'ABOUT-NLS' file on most GNU archive sites.  The most up-to-date matrix
 with full percentage details can be found at
-'https://translationproject.org/extra/matrix.html'.
+'http://translationproject.org/extra/matrix.html'.
 
 1.5 Using 'gettext' in new packages
 ===================================
@@ -1376,4 +1376,4 @@ Free Translation Project is also available for packages which are not
 developed inside the GNU project.  Therefore the information given above
 applies also for every other Free Software Project.  Contact
 '[email protected]' to make the '.pot' files available
-to the translation teams.
+to the translation teams.

INSTALL

@@ -1,8 +1,8 @@
 Installation Instructions
 *************************
 
-   Copyright (C) 1994-1996, 1999-2002, 2004-2016 Free Software
-Foundation, Inc.
+   Copyright (C) 1994-1996, 1999-2002, 2004-2017, 2020-2021 Free
+Software Foundation, Inc.
 
    Copying and distribution of this file, with or without modification,
 are permitted in any medium without royalty provided the copyright
@@ -225,7 +225,7 @@ order to use an ANSI C compiler:
 
 and if that doesn't work, install pre-built binaries of GCC for HP-UX.
 
-   HP-UX 'make' updates targets which have the same time stamps as their
+   HP-UX 'make' updates targets which have the same timestamps as their
 prerequisites, which makes it generally unusable when shipped generated
 files such as 'configure' are involved.  Use GNU 'make' instead.
 

build_aux/ar-lib

@@ -4,7 +4,7 @@
 me=ar-lib
 scriptversion=2019-07-04.01; # UTC
 
-# Copyright (C) 2010-2019 Free Software Foundation, Inc.
+# Copyright (C) 2010-2021 Free Software Foundation, Inc.
 # Written by Peter Rosin <[email protected]>.
 #
 # This program is free software; you can redistribute it and/or modify

build_aux/compile

@@ -3,7 +3,7 @@
 
 scriptversion=2018-03-07.03; # UTC
 
-# Copyright (C) 1999-2020 Free Software Foundation, Inc.
+# Copyright (C) 1999-2021 Free Software Foundation, Inc.
 # Written by Tom Tromey <[email protected]>.
 #
 # This program is free software; you can redistribute it and/or modify