[Bug libstdc++/56414] C++11 atomic are not always atomic on load and store depending on the command line on x86-64

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56414



--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> 2013-02-20 
22:12:05 UTC ---

>-fpack-struct=1



Changes the ABI so you cannot depend on the ABI change working with the

standard ABI anyways.