http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40856
--- Comment #7 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-09-19 11:05:10 UTC --- But see: http://gcc.gnu.org/ml/gcc-patches/2011-09/msg01048.html. Thus, for the time being, I'm going to use __int128_t and __uint128_t in the implementation details: using the latter to define specializations instead of __int128 and unsigned __int128 should be undetectable from the user point of view.