bug#24892: {s, }brk removed from FreeBSD 11.x and later, arm64 architecture

[Eli Zaretskii]

> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Tue, 8 Nov 2016 09:54:45 -0800
> Cc: 24892@debbugs.gnu.org
> 
> Thanks for reporting that. Although I don't have easy access to that 
> platform, I simulated the problem on FreeBSD 11 x86-64 and came up with 
> the attached patch, which I installed into the Emacs master branch. 
> Please give it a try if you can, and let me know either way. I doubt 
> whether this patch will apply to Emacs 25 and have not investigated the 
> details there.

Thanks!

I think we must have at least a workaround for this in Emacs 25.
Can't we use a similar solution in emacs-25, i.e. systems that don't
have sbrk will use their system malloc?  (I understand that on master
we use system malloc for more platforms, but we don't have to do that
on emacs-25.)