Revert "Merge commit from fork"

This reverts commit 1e2b354456.

backend/local/lchmod.go

@@ -1,16 +0,0 @@
-//go:build windows || plan9 || js || linux
-
-package local
-
-import "os"
-
-const haveLChmod = false
-
-// lChmod changes the mode of the named file to mode. If the file is a symbolic
-// link, it changes the link, not the target. If there is an error,
-// it will be of type *PathError.
-func lChmod(name string, mode os.FileMode) error {
-	// Can't do this safely on this OS - chmoding a symlink always
-	// changes the destination.
-	return nil
-}