copyfile: add an optional parameter to copy other stat data Contrary to the comment, I didn't see any evidence that we were copying atime/mtime at all. This adds a parameter to copyfile to optionally copy it and other stat data, with the default being to not copy it. Many systems don't support changing the timestamp of a symlink, but we don't need that in general anyway -- copystat is mostly useful for editors, most of which will dereference symlinks anyway.