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: Manually update copyright year,
until we fully sync with gnulib at a later stage.
* tests/sample-test: Adjust to use the single most recent year.
* src/join.c (prjoin): Check for write errors after each line.
* tests/misc/write-errors.sh: enable the test for join.
* NEWS: Mention the improvement.
* src/comm.c (writeline): Simplify by removing the unneeded STREAM
parameter. Call write_error() upon ferror().
(compare_files): Adjust to simplified writeline().
* tests/misc/write-errors.sh: Enable comm test.
* NEWS: Mention the improvement.
* src/cut.c (cut_bytes): Diagnose errors from fwrite() and putchar().
(cut_fields): Likewise.
* tests/misc/write-errors.sh: Enable the test for cut,
and augment to cover both cut_bytes() and cut_fields().
* NEWS: Mention the improvement.
* src/uniq.c (write_line): Check the output from fwrite() immediately.
(check_file): Likewise.
* tests/misc/write-errors.sh: Enable the test case.
* NEWS: Mention the improvement.
* src/od.c (dump): Check for write errors after each block written,
to exit early even with large / unbounded inputs.
* tests/misc/write-errors.sh: enable od check.
* NEWS: Mention the improvement.
Fixes https://bugs.gnu.org/64540
* cfg.mk (sc_some_programs_must_avoid_exit_failure): Adjust to
avoid false positive.
(sc_prohibit_exit_write_error): A new syntax check to prohibit
open coding error(..., "write error"); instead directing to use...
* src/system.h (write_error): ... a new function to clear stdout errors
before we explicitly diagnose a write error and exit.
* src/basenc.c: Use write_error() to ensure no repeated diagnostics.
* src/cat.c: Likewise.
* src/expand.c: Likewise.
* src/factor.c: Likewise.
* src/paste.c: Likewise.
* src/seq.c: Likewise.
* src/shuf.c: Likewise.
* src/split.c: Likewise.
* src/tail.c: Likewise.
* src/tr.c: Likewise.
* src/unexpand.c: Likewise.
* tests/misc/write-errors.sh: Remove TODOs for the fixed utilities:
expand, factor, paste, shuf, tr, unexpand.
