* lisp/emacs-lisp/nadvice.el (advice-function-mapc): Rename from advice-mapc.

* lisp/emacs-lisp/nadvice.el (advice-function-mapc): Rename from advice-mapc.
(advice-mapc): New function, using it.
(advice-function-member-p): New function.
(advice--normalize): Store the cdr in advice--saved-rewrite since
that's the part that will be changed.
(advice--symbol-function): New function.
(advice-remove): Handle removal before the function is defined.
Adjust to new advice--saved-rewrite.
(advice-member-p): Use advice-function-member-p and
advice--symbol-function.