http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53238
--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-05-09 16:44:07 UTC --- Hmm, I guess this is for the case where gthr-aix.h includes gthr-single.h, which doesn't define the C++11 interface. The configure script determined that _GLIBCXX_HAS_GTHREADS should be defined, but then that only works if gthr-posix.h gets included. A fix (maybe not the right one) would be to add the C++11 types and functions to gthr-single.h and make it define __GTHREADS_CXX0X, so that <thread> can be be compiled and the types found, even if the resulting classes can't actually be used in single-threaded mode. Another option would be for gthr-aix.h to #undef _GLBCXX_HAS_GTHREADS in the non-_THREAD_SAFE case, but I think that would be wrong, changing a property that should be fixed at configure time into one that depends on switches being used or not when the user compiles code. I won't be able to work on that until I'm back from holiday in two weeks, in the meanwhile --disable-libstdcxx-threads should allow you to bootstrap, or maybe just --disable-libstdcxx-pch
