- error (_f ("TFM header of `%s' has only %u word(s)",
- input_.name_str ().ch_C (), header_length));
+ /* Not using ngettext's plural feature here, as this message is
+ more of a programming error. */
+ error (_f ("TFM header of `%s' has only %u word (s)",
+ input_.name_string ().to_str0 (), header_length));