[NaCl SDK] Enable select/poll on TTY nodes.

native_client_sdk/src/libraries/nacl_io/mount_node_tty.h

Index: native_client_sdk/src/libraries/nacl_io/mount_node_tty.h
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node_tty.h b/native_client_sdk/src/libraries/nacl_io/mount_node_tty.h
index 0707420a0c8acc11737c56c5aa78fe5184d7774b..87c8191506d3fd0b0b7bb10479defd83afac9c00 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_node_tty.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node_tty.h
@@ -5,6 +5,7 @@
 #ifndef LIBRARIES_NACL_IO_MOUNT_NODE_TTY_H_
 #define LIBRARIES_NACL_IO_MOUNT_NODE_TTY_H_
 
+#include <poll.h>
 #include <pthread.h>
 
 #include <deque>
@@ -38,6 +39,13 @@ class MountNodeTty : public MountNodeCharDevice {
   virtual Error Tcsetattr(int optional_actions,
                           const struct termios *termios_p);
 
+  virtual uint32_t GetEventStatus() {
+    uint32_t status = POLLOUT;
+    if (is_readable_)
+      status |= POLLIN;
+    return status;
+  }
+
  private:
   virtual Error Write(size_t offs,
                       const void* buf,