* autoload.cc: Add load statement for `NtOpenFile'.

	* autoload.cc: Add load statement for `NtOpenFile'.
	* fhandler.h (fhandler_dev_raw::get_unit): New method.
	(fhandler_dev_tape::norewind): Eliminate.
	(fhandler_dev_tape::is_rewind_device): New method.
	* fhandler_raw.cc (fhandler_dev_raw::open): Open new
	fixed device name devices using NT internal method.
	Keep calling fhandler_base::open() for old mount table
	device mapping compatibility devices.
	(fhandler_dev_raw::fstat): Eliminate.  Settings are done
	by fhandler_base::fstat() already.
	* fhandler_tape.cc: Remove `norewind' usage throughout.
	* ntdll.h: Define FILE_SYNCHRONOUS_IO_NONALERT.
	Define struct _IO_STATUS_BLOCK.
	Declare NtOpenFile().
	* path.cc (get_raw_device_number): Add new approach for
	using fixed device names.
	(win32_device_name): Ditto.
	(get_device_number): Ditto.  Require POSIX path to begin
	with "/dev/".
	(mount_info::conv_to_win32_path): Call win32_device_name()
	instead of get_device_number() after evaluating mount points
	to allow changing the win32 destination path again.
	* security.cc (str2buf2uni): Remove `static' to be able to
	call function from fhandler_dev_raw::open().
	* wincap.cc: Set flag has_raw_devices appropriately.
	* wincap.h: Add flag has_raw_devices.