* dtable.cc (decode_tty): Use __ptsname to generate the slave pty name.
* fhandler_tty.cc (fhandler_pty_master::ptsname_r): Ditto.
* bsdlib.cc: Add needed includes for openpty() changes.
(openpty): Use __ptsname to generate the slave pty name. Close slave fd when
aslave == NULL.