currently the error messages have the shortopt hardcoded in them, even
when the user actually entered a longopt:
$ ./nsxiv --framerate v
nsxiv: Invalid argument for option -A: v
and as far as I see, there's no way to *reliably* tell weather we're
processing a longopt or a shortopt. perhaps we can do some shenanigangs
with `optind` but that seems finicky at best.
and it seems like other coreutils which support longopt has similar issues:
$ xargs --max-procs=z
xargs: invalid number "z" for -P option
utils like `grep` and `head` seems to work-around it by not mentioning the flag:
$ head --lines=z
head: invalid number of lines: ‘z’
$ grep --max-count=l
grep: invalid max count
this patch does the same thing as `grep/head` and omits the flag from
the error message.
Closes: https://codeberg.org/nsxiv/nsxiv/issues/368
Reviewed-on: https://codeberg.org/nsxiv/nsxiv/pulls/371
Reviewed-by: Berke Kocaoğlu <berke.kocaoglu@metu.edu.tr>