http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52839
--- Comment #13 from Alan Modra <amodra at gmail dot com> 2012-04-04 23:02:34 UTC --- Huh, so glibc has a powerpc specific pthread_once, and that one has a different bug. Lack of lwsync before atomic_increment (once_control);