maint: automate annual package-wide copyright-year update.

* .x-update-copyright: New.
* Makefile.am (EXTRA_DIST): Remove maint.mk.
* bootstrap.conf (gnulib_modules): Add maintainer-makefile and
update-copyright.  Remove gnumakefile, which is implied by
maintainer-makefile.
* cfg.mk (bootstrap-tools): Copy from old maint.mk.
* gnulib: Update.
* maint.mk: Remove, now copied from gnulib.
* examples/extexi: Add missing "(C)" in copyright statement so
update-copyright can recognize it.
* src/LR0.h: Likewise.
* src/print.h: Likewise.
* src/print_graph.h: Likewise.
* src/named-ref.c: Likewise.
* src/named-ref.h: Likewise.
* src/gram.c: Add missing comma in copyright statement.
* src/gram.h: Likewise.
(cherry picked from commit dbbb64f091)

Conflicts:

	Makefile.am
	gnulib
	maint.mk
	src/gram.h

lib/.cvsignore

@@ -4,6 +4,7 @@ Makefile.in
 argmatch.c
 argmatch.h
 basename.c
+bitrotate.h
 c-ctype.c
 c-ctype.h
 c-strcase.h
@@ -30,6 +31,7 @@ getopt.in.h
 getopt1.c
 getopt_.h
 getopt_int.h
+getpagesize.c
 gettext.h
 gnulib.mk
 hash.c
@@ -46,6 +48,7 @@ mbsinit.c
 mbswidth.c
 mbswidth.h
 memchr.c
+memchr.valgrind
 obstack.c
 obstack.h
 pipe-safer.c