update autotools version and copyright years

Makefile.in

@@ -1,7 +1,7 @@
-# Makefile.in generated by automake 1.16.3 from Makefile.am.
+# Makefile.in generated by automake 1.16.5 from Makefile.am.
 # @configure_input@
 
-# Copyright (C) 1994-2020 Free Software Foundation, Inc.
+# Copyright (C) 1994-2021 Free Software Foundation, Inc.
 
 # This Makefile.in is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -151,12 +151,10 @@ am__define_uniq_tagged_files = \
   unique=`for i in $$list; do \
     if test -f "$$i"; then echo $$i; else echo $(srcdir)/$$i; fi; \
   done | $(am__uniquify_input)`
-ETAGS = etags
-CTAGS = ctags
-CSCOPE = cscope
 DIST_SUBDIRS = $(SUBDIRS)
 am__DIST_COMMON = $(srcdir)/Makefile.in $(srcdir)/config.h.in COPYING \
-	ChangeLog compile depcomp install-sh missing tap-driver.sh
+	ChangeLog INSTALL.md README.md compile depcomp install-sh \
+	missing tap-driver.sh
 DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
 distdir = $(PACKAGE)-$(VERSION)
 top_distdir = $(distdir)
@@ -211,17 +209,17 @@ AWK = @AWK@
 CC = @CC@
 CCDEPMODE = @CCDEPMODE@
 CFLAGS = @CFLAGS@
-CPP = @CPP@
 CPPFLAGS = @CPPFLAGS@
+CSCOPE = @CSCOPE@
+CTAGS = @CTAGS@
 CYGPATH_W = @CYGPATH_W@
 DEFS = @DEFS@
 DEPDIR = @DEPDIR@
 ECHO_C = @ECHO_C@
 ECHO_N = @ECHO_N@
 ECHO_T = @ECHO_T@
-EGREP = @EGREP@
+ETAGS = @ETAGS@
 EXEEXT = @EXEEXT@
-GREP = @GREP@
 INSTALL = @INSTALL@
 INSTALL_DATA = @INSTALL_DATA@
 INSTALL_PROGRAM = @INSTALL_PROGRAM@
@@ -465,7 +463,6 @@ cscopelist-am: $(am__tagged_files)
 distclean-tags:
 	-rm -f TAGS ID GTAGS GRTAGS GSYMS GPATH tags
 	-rm -f cscope.out cscope.in.out cscope.po.out cscope.files
-
 distdir: $(BUILT_SOURCES)
 	$(MAKE) $(AM_MAKEFLAGS) distdir-am
 

README.md

@@ -46,5 +46,5 @@ Usually it should run fully functional without any argument: `alttab`.
 [no-wm](https://github.com/patrickhaller/no-wm): use X11 without a window manager  
 
 
-alttab (C) Alexander Kulak <sa-dev AT odd POINT systems> 2016-2023
+alttab (C) Alexander Kulak <sa-dev AT odd POINT systems> 2016-2024