ixfr_unlink_it
while(ixfr_unlink_it(zone->opts->name, zfile, i, 1)) {
(void)ixfr_unlink_it(zone->opts->name, zfile,
int ixfr_unlink_it(const char* zname, const char* zfile, int file_num,
(void)ixfr_unlink_it(zname, zfile, num, 0);