* fhandler.h: Move definitions of O_NOSYMLINK, O_DIROPEN and
OLD_O_NDELAY from winsup.h to here. Add O_NONBLOCK_MASK define.
* fhandler_socket.cc (fhandler_socket::close): Add hack to allow
a graceful shutdown even if shutdown() hasn't been called by the
application. Add debug output.
(fhandler_socket::ioctl): Set fhandler's NONBLOCK flag according
to FIONBIO setting.
(fhandler_socket::fcntl): Use new O_NONBLOCK_MASK define. Actually
set `request' before using it.
* fhandler_tty.cc: Use new O_NONBLOCK_MASK define throughout.
(fhandler_tty_slave::ioctl): Set fhandler's NONBLOCK flag according
to FIONBIO setting.
(fhandler_pty_master::ioctl): Ditto.
* net.cc (wsock_event::prepare): Compare WSACreateEvent return code
with `WSA_INVALID_EVENT' according to MSDN.
* syscalls.cc (_read): Use new O_NONBLOCK_MASK define.