https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64001
--- Comment #4 from Michael Hudson-Doyle <michael.hudson at canonical dot com> --- Well, it seems to report that __morestack_segments & __morestack_current_segment are always NULL for all threads. I don't understand the morestack code perfectly, but this seems a bit unlikely to actually be the case. "GNU gdb (Ubuntu 7.8-1ubuntu4) 7.8.0.20141001-cvs" seems like it should be new enough?
