On Windows, the mode bits reported by [Lstat] and [Stat] for
reparse points changed. Mount points no longer have [ModeSymlink] set,
and reparse points that are not symlinks, Unix sockets, or dedup files
now always have [ModeIrregular] set.
This behavior is controlled by the `winsymlink` setting.
For Go 1.23, it defaults to `winsymlink=1`.

	ModeSetgid     = fs.ModeSetgid     // g: setgid
	ModeCharDevice = fs.ModeCharDevice // c: Unix character device, when ModeDevice is set
	ModeSticky     = fs.ModeSticky     // t: sticky
	ModeIrregular  = fs.ModeIrregular  // ?: non-regular file; nothing else is known about this file

	// Mask for the type bits. For regular files, none will be set.
	ModeType = fs.ModeType

	ModePerm = fs.ModePerm // Unix permission bits, 0o777

			//
			// Go programs may use ModeIrregular to filter out unusual files (such as
			// raw device files on Linux, POSIX FIFO special files, and so on), so
			// to avoid files changing unpredictably from regular to irregular we will
			// consider DEDUP files to be close enough to regular to treat as such.
		default:
			m |= ModeIrregular
		}
	}
	return
}

	case syscall.S_IFLNK:
		fs.mode |= ModeSymlink
	case syscall.S_IFREG:
		// nothing to do
	case syscall.S_IFSOCK:
		fs.mode |= ModeSocket
	case _S_IFNAM, _S_IFDOOR, _S_IFPORT:
		fs.mode |= ModeIrregular
	}
	if fs.sys.Mode&syscall.S_ISGID != 0 {
		fs.mode |= ModeSetgid
	}
	if fs.sys.Mode&syscall.S_ISUID != 0 {
		fs.mode |= ModeSetuid
	}
	if fs.sys.Mode&syscall.S_ISVTX != 0 {
		fs.mode |= ModeSticky
	}

			isDir:   true,
		},
		"drwxr-xr-x 0 1970-01-01 12:00:00 home/gopher/",
		"d home/gopher/",
	},
	{
		formatTest{
			name:    "big",
			size:    0x7fffffffffffffff,
			mode:    ModeIrregular | 0o644,
			modTime: time.Date(1970, time.January, 1, 12, 0, 0, 0, time.UTC),
			isDir:   false,
		},
		"?rw-r--r-- 9223372036854775807 1970-01-01 12:00:00 big",
		"? big",
	},
	{
		formatTest{

	ModeSticky                                     // t: sticky
	ModeIrregular                                  // ?: non-regular file; nothing else is known about this file

	// Mask for the type bits. For regular files, none will be set.
	ModeType = ModeDir | ModeSymlink | ModeNamedPipe | ModeSocket | ModeDevice | ModeCharDevice | ModeIrregular

	ModePerm FileMode = 0777 // Unix permission bits
)

As of Go 1.23 (`winsymlink=1`), mount points no longer have [`os.ModeSymlink`](/pkg/os#ModeSymlink)
set, and reparse points that are not symlinks, Unix sockets, or dedup files now
always have [`os.ModeIrregular`](/pkg/os#ModeIrregular) set. As a result of these changes,
[`filepath.EvalSymlinks`](/pkg/path/filepath#EvalSymlinks) no longer evaluates
mount points, which was a source of many inconsistencies and bugs.

pkg net/http/httptrace, type ClientTrace struct, WroteHeaderField func(string, []string)
pkg net/http/httputil, type ReverseProxy struct, ErrorHandler func(http.ResponseWriter, *http.Request, error)
pkg os, const ModeIrregular = 524288
pkg os, const ModeIrregular FileMode
pkg os, const ModeType = 2399666176
pkg os, func UserCacheDir() (string, error)
pkg os/signal, func Ignored(os.Signal) bool
pkg regexp/syntax, method (Op) String() string

// for the fileInfo methods other than Name, set to the file's name, and Mode
// set to ModeIrregular.
type missingFile string

func (f missingFile) Name() string       { return string(f) }
func (f missingFile) Size() int64        { return 0 }
func (f missingFile) Mode() fs.FileMode  { return fs.ModeIrregular }
func (f missingFile) ModTime() time.Time { return time.Unix(0, 0) }

			continue
		}
		var wantType fs.FileMode
		if test.isMountPoint && winsymlink.Value() != "0" {
			// Mount points are reparse points, and we no longer treat them as symlinks.
			wantType = fs.ModeIrregular
		} else {
			// This is either a real symlink, or a mount point treated as a symlink.
			wantType = fs.ModeSymlink
		}
		if tp := fi2.Mode().Type(); tp != wantType {