bug#61960: 30.0.50; Unexec build reliably crashes during loadup

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

Andrea Corallo <akrl@sdf.org> writes:

> Po Lu <luangruo@yahoo.com> writes:
>
>> Eli Zaretskii <eliz@gnu.org> writes:
>>
>>>> From: Andrea Corallo <akrl@sdf.org>
>>>> Cc: 61960@debbugs.gnu.org, hi-angel@yandex.ru
>>>> Date: Tue, 07 Mar 2023 14:59:24 +0000
>>>> 
>>>> >   if test "${with_native_compilation}" != "no"; then
>>>> >       if test "${HAVE_PDUMPER}" = no; then
>>>> > 	 AC_MSG_ERROR(['--with-native-compilation' requires '--with-dumping=pdumper'])
>>>> >       fi
>>>> 
>>>> So IIUC we can compile emacs with both unexec and pdumper support, they
>>>> are not mutually exclusive, and we can specify which one to use for the
>>>> first dump with --with-dumping.
>>>> 
>>>> So yeah I think we have to prevent native compilation to be compiled
>>>> with unexec support, even if it's not the way Emacs is dumped the first
>>>> time.
>>>
>>> OK, then a simple change to the above condition (and maybe a slight
>>> change in the message wording as well) should achieve that, right?
>>
>> Emacs can't be built with both unexec and pdumper dumping, and configure
>> doesn't let you do that.  So what we have is fine.
>
> On emacs 29
>
> configure --without-x --with-native-compilation --with-unexec=yes --with-pdumper=yes
>
> does succeed so I don't think it is fine.

What is the resulting config.h?  The quality of configure's error
reporting has gone down in the past several years.  --with-unexec is
silently ignored if you specify --with-pdumper.