Update to latest gnulib with new copyright year.
Run "make update-copyright" and then...
* gnulib: Update included in this commit as copyright years
are the only change from the previous gnulib commit.
* tests/init.sh: Sync with gnulib to pick up copyright year.
* bootstrap: Likewise.
* tests/sample-test: Adjust to use the single most recent year.
* cfg.mk (sc_gldist_missing): Add a new target to ensure we don't
forget to distribute any new gl/ files.
* gl/local.mk: Remove generation comment since it's
now encapsulated in the syntax-check, which outputs a consumable
diff to make any future adjustments.
Also adjust ordering to that of the C locale used in the syntax check.