Digging some more, I think the issue is http://debbugs.gnu.org/cgi/bugreport.cgi?bug=24065 . Emacs trunk is depending on undefined C behaviour, which gcc 5 has started optimising, breaking the code.

I've updated https://www.emacswiki.org/emacs/GuileEmacsBuild to note this. You can work around with -fno-builtin-malloc or simply compile with clang (my current solution).

Emacs trunk has fixed this (in 4b1436b702d56eedd27a0777fc7232cdfb7ac4f6 IIUC), but I believe that commit does not exist in the guile-emacs fork.

Wilfred

On 4 September 2016 at 04:48, Stefan Husmann <stefan-husmann@t-online.de> wrote:
Wilfred Hughes <me@wilfred.me.uk> writes:

> I've had a play with the AUR packages too. The guile4emacs PKGBUILD works
> perfectly, but the guile-emacs build process segfaults when bootstrap-emacs
> attempts to load calendar/cal-loaddefs.el:
>
> make[2]: Leaving directory
> '/home/wilfred/aur/guile-emacs-git/src/guilemacs/lisp'
> if test "yes" = "yes"; then \
>   rm -f bootstrap-emacs; \
>   ln temacs bootstrap-emacs; \
> else \
>   ./temacs --batch --load loadup bootstrap || exit 1; \
>   test "X" = X ||  -zex emacs; \
>   mv -f emacs bootstrap-emacs; \
> fi
> make -C ../lisp autoloads EMACS="../src/bootstrap-emacs"
> make[2]: Entering directory
> '/home/wilfred/aur/guile-emacs-git/src/guilemacs/lisp'
> EMACSLOADPATH= '../src/bootstrap-emacs' -batch --no-site-file
> --no-site-lisp -l autoload \
>    --eval "(setq generate-autoload-cookie \";;;###cal-autoload\")" \
>    --eval "(setq generated-autoload-file (expand-file-name
> (unmsys--file-name \"calendar/cal-loaddefs.el\")))" \
>    -f batch-update-autoloads ./calendar
> make[2]: *** [Makefile:466: calendar/cal-loaddefs.el] Segmentation fault
> (core dumped)
> make[2]: Leaving directory
> '/home/wilfred/aur/guile-emacs-git/src/guilemacs/lisp'
> make[1]: *** [Makefile:805: ../lisp/loaddefs.el] Error 2
> make[1]: Leaving directory
> '/home/wilfred/aur/guile-emacs-git/src/guilemacs/src'
> make: *** [Makefile:376: src] Error 2
> ==> ERROR: A failure occurred in build().
>     Aborting...
>
> Any suggestions?
>
> On 30 August 2016 at 20:32, Wilfred Hughes <me@wilfred.me.uk> wrote:
>
Hello,

I can confirm this, but currently have no ideas what is going on
here. This definitely used to work, but gcc was updated since then.

Sorry for inconveniance. I will try to dig deeper into it.

Best Regards

Stefan