link: warn if dest exists but isn't a symlink

Signed-off-by: Christopher Larson <kergoth@gmail.com>
Simplify the 'My *' link creation

Signed-off-by: Christopher Larson <kergoth@gmail.com>
link: correct the mkdirs for toplevel files

Signed-off-by: Christopher Larson <kergoth@gmail.com>