bug#33174: 27.0.50; Dump fails on GNU/Linux ppc64le

[Thomas Fitzsimmons <fitzsim@fitzsim.org>]

Paul Eggert <eggert@cs.ucla.edu> writes:

> Thomas Fitzsimmons wrote:
>> Actually, EMACS_HEAP_EXEC is true!
>
> OK, thanks, that explains things. I installed the first attached patch
> to the emacs-26 branch as a quick hack to work around the problem,

I confirmed this works around the problem on the emacs-26 branch with
EMACS_HEAP_EXEC set in the initial build environment, and confirmed that
the build still works without it set.

> and the second attached patch to the master branch to come up with a
> better way to address the underlying issue that doesn't involve
> fiddling with environment variables. Please let us know if this
> doesn't work for your platform, as I've tested this only on x86-64.

Likewise this fixes the failure on master on my system with
EMACS_HEAP_EXEC set, and the build still works without it set.

It looks like the second patch still disables ASLR unconditionally on
PPC64.  If you want to suggest experiments I can try on my system, maybe
I can attempt a fix so that ASLR can be disabled only during dumping on
PPC64 like on other archiectures.  Or do you know that's an
impossibility for some reason?

Thanks,
Thomas