refactor: use #ifdef HAVE_SOCKADDR_UN

```bash
init.cpp:526:5: error: "HAVE_SOCKADDR_UN" is not defined, evaluates to 0 [-Werror=undef]
  526 | #if HAVE_SOCKADDR_UN
      |     ^~~~~~~~~~~~~~~~
init.cpp:541:5: error: "HAVE_SOCKADDR_UN" is not defined, evaluates to 0 [-Werror=undef]
  541 | #if HAVE_SOCKADDR_UN
      |     ^~~~~~~~~~~~~~~~
init.cpp:1318:5: error: "HAVE_SOCKADDR_UN" is not defined, evaluates to 0 [-Werror=undef]
 1318 | #if HAVE_SOCKADDR_UN
```
```
netbase.cpp:26:5: error: "HAVE_SOCKADDR_UN" is not defined, evaluates to 0 [-Werror=undef]
   26 | #if HAVE_SOCKADDR_UN
      |     ^~~~~~~~~~~~~~~~
netbase.cpp:221:5: error: "HAVE_SOCKADDR_UN" is not defined, evaluates to 0 [-Werror=undef]
  221 | #if HAVE_SOCKADDR_UN
      |     ^~~~~~~~~~~~~~~~
netbase.cpp:496:5: error: "HAVE_SOCKADDR_UN" is not defined, evaluates to 0 [-Werror=undef]
  496 | #if HAVE_SOCKADDR_UN
      |     ^~~~~~~~~~~~~~~~
netbase.cpp:531:5: error: "HAVE_SOCKADDR_UN" is not defined, evaluates to 0 [-Werror=undef]
  531 | #if HAVE_SOCKADDR_UN
      |     ^~~~~~~~~~~~~~~~
netbase.cpp:639:5: error: "HAVE_SOCKADDR_UN" is not defined, evaluates to 0 [-Werror=undef]
  639 | #if HAVE_SOCKADDR_UN
```

Author: fanquake

src/init.cpp

@@ -531,7 +531,7 @@ void SetupServerArgs(ArgsManager& argsman)
     argsman.AddArg("-maxreceivebuffer=<n>", strprintf("Maximum per-connection receive buffer, <n>*1000 bytes (default: %u)", DEFAULT_MAXRECEIVEBUFFER), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-maxsendbuffer=<n>", strprintf("Maximum per-connection memory usage for the send buffer, <n>*1000 bytes (default: %u)", DEFAULT_MAXSENDBUFFER), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-maxuploadtarget=<n>", strprintf("Tries to keep outbound traffic under the given target per 24h. Limit does not apply to peers with 'download' permission or blocks created within past week. 0 = no limit (default: %s). Optional suffix units [k|K|m|M|g|G|t|T] (default: M). Lowercase is 1000 base while uppercase is 1024 base", DEFAULT_MAX_UPLOAD_TARGET), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
-#if HAVE_SOCKADDR_UN
+#ifdef HAVE_SOCKADDR_UN
     argsman.AddArg("-onion=<ip:port|path>", "Use separate SOCKS5 proxy to reach peers via Tor onion services, set -noonion to disable (default: -proxy). May be a local file path prefixed with 'unix:'.", ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
 #else
     argsman.AddArg("-onion=<ip:port>", "Use separate SOCKS5 proxy to reach peers via Tor onion services, set -noonion to disable (default: -proxy)", ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
@@ -544,7 +544,7 @@ void SetupServerArgs(ArgsManager& argsman)
     argsman.AddArg("-peerblockfilters", strprintf("Serve compact block filters to peers per BIP 157 (default: %u)", DEFAULT_PEERBLOCKFILTERS), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-txreconciliation", strprintf("Enable transaction reconciliations per BIP 330 (default: %d)", DEFAULT_TXRECONCILIATION_ENABLE), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CONNECTION);
     argsman.AddArg("-port=<port>", strprintf("Listen for connections on <port> (default: %u, testnet: %u, signet: %u, regtest: %u). Not relevant for I2P (see doc/i2p.md).", defaultChainParams->GetDefaultPort(), testnetChainParams->GetDefaultPort(), signetChainParams->GetDefaultPort(), regtestChainParams->GetDefaultPort()), ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
-#if HAVE_SOCKADDR_UN
+#ifdef HAVE_SOCKADDR_UN
     argsman.AddArg("-proxy=<ip:port|path>", "Connect through SOCKS5 proxy, set -noproxy to disable (default: disabled). May be a local file path prefixed with 'unix:' if the proxy supports it.", ArgsManager::ALLOW_ANY | ArgsManager::DISALLOW_ELISION, OptionsCategory::CONNECTION);
 #else
     argsman.AddArg("-proxy=<ip:port>", "Connect through SOCKS5 proxy, set -noproxy to disable (default: disabled)", ArgsManager::ALLOW_ANY | ArgsManager::DISALLOW_ELISION, OptionsCategory::CONNECTION);
@@ -1325,7 +1325,7 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
             std::string host_out;
             uint16_t port_out{0};
             if (!SplitHostPort(socket_addr, port_out, host_out)) {
-#if HAVE_SOCKADDR_UN
+#ifdef HAVE_SOCKADDR_UN
                 // Allow unix domain sockets for some options e.g. unix:/some/file/path
                 if (!unix || socket_addr.find(ADDR_PREFIX_UNIX) != 0) {
                     return InitError(InvalidPortErrMsg(arg, socket_addr));

src/netbase.cpp

@@ -23,7 +23,7 @@
 #include <limits>
 #include <memory>
 
-#if HAVE_SOCKADDR_UN
+#ifdef HAVE_SOCKADDR_UN
 #include <sys/un.h>
 #endif
 
@@ -218,7 +218,7 @@ CService LookupNumeric(const std::string& name, uint16_t portDefault, DNSLookupF
 
 bool IsUnixSocketPath(const std::string& name)
 {
-#if HAVE_SOCKADDR_UN
+#ifdef HAVE_SOCKADDR_UN
     if (name.find(ADDR_PREFIX_UNIX) != 0) return false;
 
     // Split off "unix:" prefix
@@ -527,7 +527,7 @@ std::unique_ptr<Sock> CreateSockOS(int domain, int type, int protocol)
         return nullptr;
     }
 
-#if HAVE_SOCKADDR_UN
+#ifdef HAVE_SOCKADDR_UN
     if (domain == AF_UNIX) return sock;
 #endif
 
@@ -638,7 +638,7 @@ std::unique_ptr<Sock> Proxy::Connect() const
 
     if (!m_is_unix_socket) return ConnectDirectly(proxy, /*manual_connection=*/true);
 
-#if HAVE_SOCKADDR_UN
+#ifdef HAVE_SOCKADDR_UN
     auto sock = CreateSock(AF_UNIX, SOCK_STREAM, 0);
     if (!sock) {
         LogPrintLevel(BCLog::NET, BCLog::Level::Error, "Cannot create a socket for connecting to %s\n", m_unix_socket_path);