bug#30364: 26.0.91; thread crash on macos

[Eli Zaretskii]

> Cc: npostavs@gmail.com, 30364@debbugs.gnu.org,
>  npostavs@users.sourceforge.net, alan@idiocy.org
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Mon, 19 Feb 2018 09:24:32 -0800
> 
> A 64-bit Emacs should need more stack space than a 32-bit Emacs, yes. It 
> wouldn't be double the space, since not everything on the stack is a pointer 
> or 
> an EMACS_INT. If you really want to fine-tune it you can also depend on the 
> width of EMACS_INT. Getting it "just right" would be a bit tricky.
> 
> 8 MiB/thread for 64-bit Emacs sounds OK to me. I wouldn't cheap out on 64-bit 
> platforms.

Thanks.  I guess we should go with 4MB for 32-bit builds and 8MB for
64-bit.