bug#67005: 30.0.50; improve nadivce/comp/trampoline handling

[Stefan Monnier]

>>> +  (when purify-flag
>>> +    (error "Invalid pre-dump advice on %s" symbol))
>>>    (let* ((f (symbol-function symbol))
>>>      (nf (advice--normalize symbol f)))
>>>      (unless (eq f nf) (fset symbol nf))
>>
>> The patch LGTM thanks, just one question: should we guard in advice.el
>> as well just to stay on the safe side?
>
> Since `defadvice` is now marked as obsolete, it seems highly unlikely
> that we'd end up adding an old-style advice to a preloaded file.

More to the point: no it's not necessary since `advice.el` uses
`advice-add` to install its pieces of advice, so the test in
`nadvice.el` already covers it.


        Stefan