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

[Paul Eggert <eggert@cs.ucla.edu>]

I built and ran Emacs master on two CentOS 7 ppc64le platforms with no trouble. 
So the problem is not GNU/Linux ppc64le per se; it's something more specific to 
your platform. Here are some characteristics of my builds:

Emacs master branch commit 3dd16a89bf410d77e9ddc41cbfbbd4b343928d6d

./configure --with-x-toolkit=no --with-xpm=no --with-jpeg=no --with-png=no 
--with-gif=no --with-tiff=no

Both machines were CentOS 7. On both of them, 
/proc/sys/kernel/randomize_va_space is 2, just as in your Debian machine.

uname -rvmpi reported the following (respectively):
3.10.0-693.11.6.el7.ppc64le #1 SMP Thu Jan 4 18:15:24 GMT 2018 ppc64le ppc64le 
ppc64le
4.14.0-49.13.1.el7a.ppc64le #1 SMP Wed Sep 26 21:58:41 GMT 2018 ppc64le ppc64le 
ppc64le

gcc --version reported the following (respectively):
gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-16)
gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-28)

On the machine running 4.14.0, there was no setfattr or getfattr command; 
however, ./temacs personality (0xffffffff) returned 0x40000 (i.e., 
ADDR_NO_RANDOMIZE) and so ./temacs did not reexec itself. I don't know why it 
returned 0x40000; even little programs that only call personality (0xffffffff) 
return 0x40000 on this platform.