phpGH-16889: stream_select() timeout useless for pipes on Windows

Pipes are blocking on Windows, but `php_select()` always returns them
as ready for read/write.  This renders the `stream_select()` timeout
useless, what can cause a following read to block for a very long time.

While there is no general fix (and least not within reach for a stable
version), we can at least cater to the important case of read pipes by
peeking the pipe to check whether data is available.  If there is none,
we do not add the handle to the read set.

Author: cmb69

ext/standard/tests/streams/gh16889.phpt

@@ -0,0 +1,26 @@
+--TEST--
+GH-16889 (stream_select() timeout useless for pipes on Windows)
+--FILE--
+<?php
+$desc = [
+    ["pipe", "r"],
+    ["pipe", "w"],
+    ["pipe", "w"],
+];
+// open process which won't produce output for 10s
+$proc = proc_open([PHP_BINARY, "-r", "sleep(10); echo 'finish';"], $desc, $pipes);
+$read = [$pipes[1]];
+$write = null;
+$except = null;
+$time0 = microtime(true);
+// select STDOUT pipe of process for 1ms
+if (stream_select($read, $write, $except, 0, 1000)) {
+    var_dump(fread($read[0], 1));
+}
+// avoid blocking of finishing the test process
+proc_terminate($proc);
+$time1 = microtime(true);
+var_dump($time1 - $time0 < 1);
+?>
+--EXPECT--
+bool(true)

win32/select.c

@@ -21,7 +21,7 @@
  * - If you supply only sockets, this simply passes through to winsock select().
  * - If you supply file handles, there is no way to distinguish between
  *   ready for read/write or OOB, so any set in which the handle is found will
- *   be marked as ready.
+ *   be marked as ready. Pipes will be checked if they are ready for read, though.
  * - If you supply a mixture of handles and sockets, the system will interleave
  *   calls between select() and WaitForMultipleObjects(). The time slicing may
  *   cause this function call to take up to 100 ms longer than you specified.
@@ -135,15 +135,20 @@ PHPAPI int php_select(php_socket_t max_fd, fd_set *rfds, fd_set *wfds, fd_set *e
 				for (i = 0; i < n_handles; i++) {
 					if (WAIT_OBJECT_0 == WaitForSingleObject(handles[i], 0)) {
 						if (SAFE_FD_ISSET(handle_slot_to_fd[i], rfds)) {
-							FD_SET((uint32_t)handle_slot_to_fd[i], &aread);
+							DWORD avail_read = 0;
+							if (!PeekNamedPipe(handles[i], NULL, 0, NULL, &avail_read, NULL) || avail_read > 0) {
+								FD_SET((uint32_t)handle_slot_to_fd[i], &aread);
+								retcode++;
+							}
 						}
 						if (SAFE_FD_ISSET(handle_slot_to_fd[i], wfds)) {
 							FD_SET((uint32_t)handle_slot_to_fd[i], &awrite);
+							retcode++;
 						}
 						if (SAFE_FD_ISSET(handle_slot_to_fd[i], efds)) {
 							FD_SET((uint32_t)handle_slot_to_fd[i], &aexcept);
+							retcode++;
 						}
-						retcode++;
 					}
 				}
 			}