[Toybox] Behavior difference between toybox and ubuntu?

[Rob Landley]

And lo:

  $ ln -s link link
  $ ln -sf / link
  ln: failed to access ‘link’: Too many levels of symbolic links
  $ ./ln -sf / link
  $ ls -l link
  lrwxrwxrwx 1 landley landley 1 Apr  8 16:55 link -> /

I.E. When the destination is a symlink, ubuntu ln -sf tries to follow it and
dies if it can't, but toybox deletes it if the symlink() call fails (for any
reason) and tries again, which works.

I _think_ toybox is right here? But it's causing "make test_readlink" to fail
when used with the ubuntu host $PATH instead of a toybox host $PATH. :P

Rob