message: Use string_view for the constexpr strings
diff: @@ -58,10 +58,10 @@ namespace ip {
  namespace {
  // Dummy port to resolve empty string with getaddrinfo.
  -constexpr auto dummy_port = "42";
  -constexpr auto v4_any_addr = "0.0.0.0";
  -constexpr auto v6_any_addr = "::";
  -constexpr auto localhost = "localhost";
  +constexpr string_view dummy_port = "42";
  +constexpr string_view v4_any_addr = "0.0.0.0";
  +constexpr string_view v6_any_addr = "::";
  +constexpr string_view localhost = "localhost";
  void* fetch_in_addr(int family, sockaddr* addr) {
  if (family == AF_INET)
  @@ -115,7 +115,7 @@ std::vector<ip_address> resolve(string_view host) {
  addrinfo* tmp = nullptr;
  std::string host_str{host.begin(), host.end()};
  if (getaddrinfo(host.empty() ? nullptr : host_str.c_str(),
  - host.empty() ? dummy_port : nullptr, &hint, &tmp)
  + host.empty() ? dummy_port.data() : nullptr, &hint, &tmp)
  != 0)
  return {};
  std::unique_ptr<addrinfo, decltype(freeaddrinfo)*> addrs{tmp, freeaddrinfo};
  @@ -151,9 +151,9 @@ std::string hostname() {
  std::vector<ip_address> local_addresses(string_view host) {
  using adapters_ptr = std::unique_ptr<IP_ADAPTER_ADDRESSES, void (*)(void*)>;
  using wbuf_ptr = std::unique_ptr<IP_ADAPTER_ADDRESSES, void (*)(void*)>;
  - if (!host.empty() && host.compare(v4_any_addr) == 0)
  + if (host == v4_any_addr)
  return {ip_address{make_ipv4_address(0, 0, 0, 0)}};
  - if (!host.empty() && host.compare(v6_any_addr) == 0)
  + if (host == v6_any_addr)
  return {ip_address{}};
  ULONG len = 0;
  auto err = GetAdaptersAddresses(AF_UNSPEC, GAA_FLAG_INCLUDE_PREFIX, nullptr,
  @@ -214,9 +214,9 @@ std::vector<ip_address> local_addresses(string_view host) {
  #else // CAF_WINDOWS
  std::vector<ip_address> local_addresses(string_view host) {
  - if (!host.empty() && host.compare(v4_any_addr) == 0)
  + if (host == v4_any_addr)
  return {ip_address{make_ipv4_address(0, 0, 0, 0)}};
  - if (!host.empty() && host.compare(v6_any_addr) == 0)
  + if (host == v6_any_addr)
  return {ip_address{}};
  ifaddrs* tmp = nullptr;
  if (getifaddrs(&tmp) != 0)
  