connectd/tests: fix test_announce_and_connect_via_dns on macOS

Two issues caused this test to fail or produce BROKEN log messages on macOS:

1. macOS does not include 'localhost.localdomain' in /etc/hosts by default,
   so the test's DNS-resolve step fails immediately.  Skip with a clear
   message if the hostname is not resolvable.

2. On macOS/BSD, AI_ADDRCONFIG is implemented by opening temporary probe
   sockets to test IPv4/IPv6 connectivity.  Those sockets are not registered
   with the io framework, so dev_report_fds() flags them as unowned (BROKEN).
   Guard AI_ADDRCONFIG with #ifndef __APPLE__ so Linux keeps the optimization
   while macOS avoids the fd-leak.

Changelog-None

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: nGoline

connectd/connectd.c

@@ -1134,7 +1134,14 @@ static void try_connect_one_addr(struct connecting *connect)
 			hints.ai_socktype = SOCK_STREAM;
 			hints.ai_family = AF_UNSPEC;
 			hints.ai_protocol = 0;
+			/* AI_ADDRCONFIG speeds up connects on single-stack hosts by
+			 * pruning unreachable address families.  Skip on macOS/BSD
+			 * where it opens temporary probe sockets that confuse our
+			 * fd-leak checker. */
+#ifndef __APPLE__
 			hints.ai_flags = AI_ADDRCONFIG;
+#endif
+
 			gai_err = getaddrinfo((char *)addr->u.wireaddr.wireaddr.addr,
 					      tal_fmt(tmpctx, "%d",
 						      addr->u.wireaddr.wireaddr.port),

tests/test_gossip.py

@@ -202,6 +202,13 @@ def test_announce_and_connect_via_dns(node_factory, bitcoind):
         - --disable-dns is needed so the first node does not announce 127.0.0.1 itself.
         - 'dev-allow-localhost' must not be set, so it does not resolve localhost anyway.
     """
+    # localhost.localdomain is not present in /etc/hosts on macOS by default.
+    # See https://github.com/ElementsProject/lightning/issues/9012
+    try:
+        socket.getaddrinfo('localhost.localdomain', 12345, 0, socket.SOCK_STREAM)
+    except socket.gaierror:
+        pytest.skip("localhost.localdomain not resolvable; add '127.0.0.1 localhost.localdomain' to /etc/hosts")
+
     opts1 = {'disable-dns': None,
              'announce-addr': ['dns:localhost.localdomain:12345'],  # announce dns
              'bind-addr': ['127.0.0.1:12345', '[::1]:12345']}   # and bind local IPs