(defun mouse-yank-at-click (click arg)
"Insert the last stretch of killed text at the position clicked on.
-Also move point to one end of the text thus inserted (normally the end).
+Also move point to one end of the text thus inserted (normally the end),
+and set mark at the beginning..
Prefix arguments are interpreted as with \\[yank].
If `mouse-yank-at-point' is non-nil, insert at point
regardless of where you click."