http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58080
--- Comment #13 from Paolo Carlini <paolo.carlini at oracle dot com> --- If you need help, luckily today Jason provided a nice HOWTO here (the only difference is that you want trunk, not 4_8-branch): http://gcc.gnu.org/ml/gcc-bugs/2013-08/msg00320.html