(defun yf-kill-new-second-pos (string)
  "Make STRING the second kill in kill ring. Mainly to
be used in order to redo all of the evil delete commands
such that they don't overwrite what is in the system clipboard,
but are still accessable by `helm-show-kill-ring' and similar commands.

Obviously therefore given the intended use of this function, unlike `kill-new'
it does not worry about whether or not interprogram paste is set or not,
and always acts like it is not.

It also does not change the `kill-ring-yank-pointer', as it is expected that the
paste system clipboard buffer is still intended to be what the user wants
to yank.

Much of the code here is borrowed from `kill-new' in simple.el"

  ;; start stuff that is ripped straight from kill-new
  (unless (and kill-do-not-save-duplicates
           ;; cadr instead of car
           (equal-including-properties string (cadr kill-ring)))
    (setcdr kill-ring (cons string (cdr kill-ring)))
    (if (> (length kill-ring) kill-ring-max)
    (set-cdr (nthcdr (1- kill-ring-max) kill-ring) kill-ring) nil)))