make stream_select return feof streams

Thankfully an easier change than I had hoped thanks to @sgolemon. This will hopefully let us run Symphony's `proc_open` wrappers.

hphp/runtime/ext/ext_socket.cpp

@@ -652,7 +652,7 @@ Variant f_socket_select(VRefParam read, VRefParam write, VRefParam except,
   count = 0;
   int nfds = 0;
   if (!read.isNull()) {
-    sock_array_from_fd_set(read, fds, nfds, count, POLLIN|POLLERR);
+    sock_array_from_fd_set(read, fds, nfds, count, POLLIN|POLLERR|POLLHUP);
   }
   if (!write.isNull()) {
     sock_array_from_fd_set(write, fds, nfds, count, POLLOUT|POLLERR);

hphp/test/slow/ext_socket/select_feof.php

@@ -0,0 +1,27 @@
+<?php
+
+$descriptors = array(
+  array('pipe', 'r'), // stdin
+  array('pipe', 'w'), // stdout
+  array('pipe', 'w'), // stderr
+);
+
+$process = proc_open('echo "hi"', $descriptors, $pipes);
+
+// Hopefully echo is done in 1 second...
+sleep(1);
+
+for ($i = 0; $i < 2; $i++) {
+  $r = array($pipes[1], $pipes[2]);
+  $w = null;
+  $e = null;
+  var_dump(stream_select($r, $w, $e, 0, 200000));
+
+  foreach ($r as $pipe) {
+    var_dump(
+      array_search($pipe, $pipes),
+      fread($pipe, 8192),
+      feof($pipe)
+    );
+  }
+}

hphp/test/slow/ext_socket/select_feof.php.expect

@@ -0,0 +1,15 @@
+int(2)
+int(1)
+string(3) "hi
+"
+bool(false)
+int(2)
+string(0) ""
+bool(true)
+int(2)
+int(1)
+string(0) ""
+bool(true)
+int(2)
+string(0) ""
+bool(true)