* 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/ntdll.h

@@ -9,6 +9,7 @@
    details. */
 
 #define STATUS_INFO_LENGTH_MISMATCH ((NTSTATUS) 0xc0000004)
+#define FILE_SYNCHRONOUS_IO_NONALERT 32
 
 typedef enum _SYSTEM_INFORMATION_CLASS
 {
@@ -132,6 +133,12 @@ typedef struct _SYSTEM_PROCESSES
   SYSTEM_THREADS Threads[1];
 } SYSTEM_PROCESSES, *PSYSTEM_PROCESSES;
 
+typedef struct _IO_STATUS_BLOCK
+{
+  NTSTATUS Status;
+  ULONG Information;
+} IO_STATUS_BLOCK, *PIO_STATUS_BLOCK;
+
 /* Function declarations for ntdll.dll.  These don't appear in any
    standard Win32 header.  */
 extern "C"
@@ -144,6 +151,8 @@ extern "C"
   NTSTATUS NTAPI NtMapViewOfSection (HANDLE, HANDLE, PVOID *, ULONG, ULONG,
 				     PLARGE_INTEGER, PULONG, SECTION_INHERIT,
 				     ULONG, ULONG);
+  NTSTATUS NTAPI NtOpenFile (PHANDLE, ACCESS_MASK, POBJECT_ATTRIBUTES,
+			     PIO_STATUS_BLOCK, ULONG, ULONG);
   NTSTATUS NTAPI NtOpenSection (PHANDLE, ACCESS_MASK, POBJECT_ATTRIBUTES);
   NTSTATUS NTAPI NtQuerySystemInformation (SYSTEM_INFORMATION_CLASS,
 					   PVOID, ULONG, PULONG);