https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71767
--- Comment #5 from Jeffrey Walton <noloader at gmail dot com> --- (In reply to Dominique d'Humieres from comment #4) > I see the problem after having updated to Xcode 8.0. I am currently testing > the following patch > Just an FYI... Clang 3.7 and below do not witness the problem. Clang 3.8 and above do. If you are working on OS X and want to avoid iTunes accounts and the App Store, then you can duplicate with MacPorts: # port install clang-3.8 # port install gcc6 # ln -s /opt/local/bin/clang /opt/local/bin/clang-3.8 (My apologies if I got the link backwards; I always do it in real life, too). Then: CC=/opt/local/bin/gcc-mp-6 CFLAGS="-Wa,-q" make Creating the link and using the full path allows you to keep MacPorts off-path. I keep it off-path to avoid cross-pollination in a testing environment.