Add missing keyword=POPT_ line to xgettext extraction.
Add missing keyword=POPT_ line to xgettext extraction.

flatzo/popt,GerHobbelt/POPT,flatzo/popt,devzero2000/POPT,GerHobbelt/POPT,devzero2000/POPT,devzero2000/POPT,GerHobbelt/POPT