Gnulib notes:

Notice from module error:
  If you are using GNU gettext version 0.16.1 or older, add the following options
  to XGETTEXT_OPTIONS in your po/Makevars:
    --flag=error:3:c-format --flag=error_at_line:5:c-format
Notice from module vasprintf:
  If you are using GNU gettext version 0.16.1 or older, add the following options
  to XGETTEXT_OPTIONS in your po/Makevars:
    --flag=asprintf:2:c-format --flag=vasprintf:2:c-format
