- Jakub Hrozek renamed addrttl and addr6ttl structs to ares_addrttl and

  ares_addr6ttl in order to prevent name space pollution, along with
  necessary changes to code base and man pages.This change does not break
  ABI, there is no need to recompile existing applications. But existing
  applications using these structs with the old name will need source code
  adjustments when recompiled using c-ares 1.6.1.