* 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.

winsup/cygwin/fhandler.h

@@ -476,14 +476,14 @@ protected:
 public:
   ~fhandler_dev_raw (void);
 
+  int get_unit () { return unit; }
+
   int open (path_conv *, int flags, mode_t mode = 0);
   int close (void);
 
   int raw_read (void *ptr, size_t ulen);
   int raw_write (const void *ptr, size_t ulen);
 
-  int __stdcall fstat (struct stat *buf, path_conv *) __attribute__ ((regparm (2)));
-
   int dup (fhandler_base *child);
 
   int ioctl (unsigned int cmd, void *buf);
@@ -511,9 +511,10 @@ public:
 
 class fhandler_dev_tape: public fhandler_dev_raw
 {
-  int norewind;
   int lasterr;
 
+  bool is_rewind_device () { return get_unit () < 128; }
+
 protected:
   virtual void clear (void);