* dtable.cc (POSIX_NAMED_PIPE): New define.

* dtable.cc (POSIX_NAMED_PIPE): New define.
(POSIX_NAMED_PIPE_LEN): Ditto.
(dtable::add_archetype): Use crealloc_abort.
(dtable::init_std_file_from_handle): Specifically detect pipe stdin/stdout.
Pass name to build_fh_dev so that proper name is recorded.  Use binmode of fh
if it is set before using get_default_mode.  Set proper read/write access when
calling init().
(handle_to_fn): Handle pipes.
* fhandler.cc (fhandler_base::wait_overlapped): Add some debugging.
* fhandler.h (fhandler_base::set_name): Default to just setting the path_conv
name.
(fhandler_pipe::init): Declare.
* pipe.cc (struct pipesync): New struct.
(getov_result): New function.  Blocks and retrieves the result of an overlay
I/O operation.
(pipe_handler): New function.
(pipesync::pipesync): New function.  Initializer for pipesync struct.
(handler_pipe::init): Define.  Detects attempts to set up a "native" pipe
fhandler and creates a thread which accepts input from or output to the
non-cygwin pipe, creating a cygwin pipe wrapper around the non-cygwin pipe.
(fhandler_pipe::create): Add pipe-specific flags to call to init().
* exceptions.cc (ctrl_c_handler): Lock process while we determine what to do.