* devices.in (dev_cygdrive_storage): Map to \Device\Null.

(dev_storage): Map /dev and /dev/windows to \Device\Null.
	* devices.cc: Regenerate.
	* dir.cc (opendir): Create unique id.  Explain why.
	* fhandler.h (fhandler_dev::get_dev): Implement inline.
	(fhandler_cygdrive::close): Drop declaration.
	(fhandler_cygdrive::get_dev): Implement inline.
	(fhandler_windows::get_hwnd): Ditto.
	(fhandler_windows::set_close_on_exec): Drop declaration.
	(fhandler_windows::fixup_after_fork): Ditto.
	* fhandler_dev.cc (fhandler_dev::open): Call fhandler_disk_file::open
	without O_CREAT flag.  Explain why.  Create \Device\Null handle if
	/dev/ doesn't actually exist.
	(fhandler_dev::close): Drop nohandle case.
	(fhandler_dev::fstatvfs): Drop nohandle check.  Test for fs_got_fs
	instead.  Set ST_RDONLY fs flag for simulated /dev.
	(fhandler_dev::opendir): If /dev doesn't exist, call open() to create
	fake \Device\Null handle.  Don't set nohandle.  Set dir_exists
	correctly.
	(fhandler_dev::rewinddir): Call fhandler_disk_file::rewinddir only if
	/dev is a real directory.
	* fhandler_disk_file.cc (fhandler_disk_file::opendir): If called for
	the cygdrive dir, call open() to create fake \Device\Null handle.
	Only attach __DIR_mounts buffer to dir if not called for cygdrive dir.
	Don't set nohandle.
	(fhandler_cygdrive::open): Create \Device\Null handle.
	(fhandler_cygdrive::close): Remove.
	(fhandler_cygdrive::fstatvfs): Set ST_RDONLY fs flag.
	* fhandler_windows.cc (fhandler_windows::open): Create \Device\Null
	handle.
	(fhandler_windows::read): Don't add io_handle to WFMO handle array.
	Change subsequent test for return value accordingly.  Fix test for
	"message arrived".
	(fhandler_windows::set_close_on_exec): Remove.
	(fhandler_windows::fixup_after_fork): Remove.
	* path.h (path_conv::set_path): Make sure wide_path is NULL when
	setting a new path.
	* select.cc (peek_windows): Use correct hWnd value, not io_handle.
	(fhandler_windows::select_read): Don't use io_handle as wait object.
	(fhandler_windows::select_write): Ditto.
	(fhandler_windows::select_except): Ditto.

winsup/cygwin/path.h

@@ -380,6 +380,7 @@ class path_conv
       cfree (modifiable_path ());
     char *new_path = (char *) cmalloc_abort (HEAP_STR, strlen (p) + 7);
     strcpy (new_path, p);
+    cfree_and_null (wide_path);
     return path = new_path;
   }
   bool is_binary ();