https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70238
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to Jonathan Wakely from comment #2) > Not a regression, it is unsupported to mix C++11 objects from gcc4 and gcc5. Just to clarify - the mixed objects are the app built with gcc4 and libstdc++.so.6 built from gcc5 sources. I wouldn't have called this "mix C++11 objects from gcc4 and gcc5" but I can see your reasoning. Other places in libstdc++.so.6 built from gcc5 sources seem to care to preserve the ABI for example by putting new things in an inline namespace (like in this case std::error_category). So I thought std::future_category was an oversight (one we can't fix retro-actively of course).
