* isearch.el (isearch-wrap-function)

* isearch.el (isearch-wrap-function)
(isearch-push-state-function): New defvars.
(isearch-pop-fun-state): New defsubst.
(isearch-top-state): Call function saved in `isearch-pop-fun-state'.
(isearch-push-state): Set the result of calling
`isearch-push-state-function' to the `isearch-pop-fun-state' field.
(isearch-cancel): Call function saved in `isearch-pop-fun-state' to
restore the mode-specific starting point of terminated search.
(isearch-abort): Call `isearch-cancel' instead of its duplicated code.
(isearch-repeat): Call `isearch-wrap-function' if defined.
(isearch-message-prefix): Don't add prefix "over" to the message
for wrapped search if `isearch-wrap-function' is defined.
(isearch-search): Call function saved in `isearch-pop-fun-state' to
restore the mode-specific starting point of failed search.