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

[Jens Schmidt via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> But this reminds me that some people do their own preload/dump,
> sometimes with a crapload of extra packages, in which case the
> probability that some of them use advice-add is rather high.

Ok.

> IIUC the the above `error` is not technically indispensable (the code
> will still work mostly right, beside some issues about the docstrings
> that affect only actual C-code subrs and not native-compiled subrs), so
> it would be better to demote the above `error` to a warning.

Eh, just used the first function that came to my mind, `warn', with the
following result:

  Error: error ("Attempt to autoload warn while preparing to dump")
    mapbacktrace(#[1028 "\1\4\203\24\0\301\302!\210\300\4!\210\301\303!\210\202\35\0\301\304!\210\3\3B\262\1\211\2035\0\300\1@!\210\211A\211\262\2\2035\0\301\305!\210\202!\0\301\306!\207" [prin1 princ "  " "(" "  (" " " ")\n"] 7 "\n\n(fn EVALD FUNC ARGS FLAGS)"])
    debug-early-backtrace()
    debug-early(error (error "Attempt to autoload warn while preparing to dump"))
    warn("Invalid pre-dump advice on %s" emacs-lisp-byte-compile)
    advice-add(emacs-lisp-byte-compile :before ignore)
    load("progmodes/elisp-mode")
    load("loadup.el")

How would one warn during bootstrap?  And would this be noticed?  Or do
we have a chance to distinguish Emacs-only builds from those with extra
packages?

Thanks.