Build failure on macOS

[Angelo Graziosi]

The current master (2e3ec402938) fails to build on macOS 10.13.6. 

Simple test case to reproduce:

wget https://git.savannah.gnu.org/cgit/emacs.git/snapshot/emacs-master.tar.gz

aunpack emacs-master.tar.gz

cd emacs-master

./autogen.sh
./configure --with-ns
make
[...]
/Applications/Xcode.app/Contents/Developer/usr/bin/make -C ../lisp 
update-subdirs
cp -f temacs bootstrap-emacs
rm -f bootstrap-emacs.pdmp
./temacs --batch  -l loadup --temacs=pbootstrap
make[1]: *** [bootstrap-emacs.pdmp] Segmentation fault: 11
make: *** [src] Error 2

Some change in the last month caused this. I build monthly Emacs.

Angelo