Build failure on ppc64el in Emacs 24.5

[Rob Browning <rlb@defaultvalue.org>]

The most recent Debian package version won't build on ppc64el, failing
with

  emacs: Program segment above .bss in
  /«BUILDDIR»/emacs24-24.5+1/debian/build-x/src/temacs

Which I suspect may be related to (fixed by) this change in emacs-25:

  commit c9fd597a4cffcae873b25381ee8cc755f0debe95
  Author: Paul Eggert <eggert@cs.ucla.edu>
  Date:   Mon Nov 16 17:48:08 2015 -0800

    ELF unexec: align section header
    
    This ports the recent unexelf.c changes to Fedora x86-64
    when configured with GCC’s -fsanitize=undefined option.
    * src/unexelf.c (unexec): Align new_data2_size to a multiple
    of ElfW (Shdr)’s alignment, so that NEW_SECTION_H returns a
    pointer aligned appropriately for its type.

However, at least from a quick glance, it looks like that patch might
not apply very easily to emacs-24.  So before I delve, I wanted to ask
about it here.

I suppose if the 25 release is fairly close, I could also consider just
spending the time there, and then (if everything works out) removing
emacs24 from sid/stretch (the next release), which would be *great*.
(Of course that assumes this issue won't affect jessie (stable).)

cf. https://debbugs.gnu.org/cgi/bugreport.cgi?bug=20614
    https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=808347

Thanks
-- 
Rob Browning
rlb @defaultvalue.org and @debian.org
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