> [: Primoz PETERLIN :]
> Apparently, msgfmt interprets "% o" in the help text of the --goal option
> as a format specifier.

When that happens, you add such a comment line just before the problematic
gettext call:

  /* xgettext: no-c-format */
  gettext("...93% of width...")

The extracted message will then have no-c-format flag instead of c-format,
thus not triggering format validation. This is documented in section 4.6 of
Gettext manual.

-- 
Chusslove Illich (Часлав Илић)