My previous commits meant to bring our wc's output and behavior in line
with GNU's. There should be tests that check for these changes!
I found a stupid bug in my own changes, I was not adding 1 to the
indexes produced by .enumerate() when printing errors.
When this option is present, the files argument is not processed. This option processes the file list from provided file, splitting them by the ascii NUL (\0) character. When files0-from is '-', the file list is processed from stdin.
