* NEWS: wc accepts a new option --files0-from=FILE, where FILE

* NEWS: wc accepts a new option --files0-from=FILE, where FILE
contains a list of NUL-separated file names.

* src/wc.c: Include "readtokens.h".
(usage): Describe the new option, and adjust the `Usage':
with this option, no FILE may be specified on the command line.
(main): Handle the new option.
* tests/misc/wc-files0: New tests, for the above.
* tests/misc/wc-files0-from: Likewise.
* tests/misc/Makefile.am (TESTS): Add wc-files0.