Fix GH-24171: Slow stream_socket_client() connect on Windows

On Windows, php_network_connect_socket() calls getsockopt(SO_ERROR)
right after select() reports that the non-blocking connect completed.
Inside mswsock, SockIsSocketConnected() can then race with mswsock's
own async thread and wait on an internal completion port with a 10 ms
timeout, so the call often blocks for 10-25 ms.

Winsock reports a successful non-blocking connect in writefds and a
failed one in exceptfds, and we already poll for POLLOUT|POLLPRI. So
when only POLLOUT is set, the connect has succeeded and getsockopt()
can be skipped.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: vibbow

NEWS

@@ -18,6 +18,11 @@ PHP                                                                        NEWS
   . Fixed chown() and lchown() failing to resolve user names in ZTS builds
     when getpwnam_r() needs a larger buffer. (Ilia Alshanetsky)
 
+- Streams:
+  . Fixed bug GH-24171 (stream_socket_client()/fsockopen() connect on Windows
+    is ~10-25 ms slow because getsockopt(SO_ERROR) stalls in mswsock).
+    (vibbow)
+
 22 Oct 2026, PHP 8.4.27
 
 - BCMath:

main/network.c

@@ -418,6 +418,13 @@ PHPAPI int php_network_connect_socket(php_socket_t sockfd,
 			ret = -1;
 		} else if (n == 0) {
 			error = PHP_TIMEOUT_ERROR_VALUE;
+#ifdef PHP_WIN32
+		} else if ((n & POLLOUT) && !(n & POLLPRI)) {
+			/* Writable and not in exceptfds: the connect succeeded (see the
+			 * comment above). Skip getsockopt(SO_ERROR) here, as calling it
+			 * right after the connection completes can block for 10-25ms. */
+			error = 0;
+#endif
 		} else {
 			len = sizeof(error);
 			/* BSD-derived systems set errno correctly.