I have tried all the boost macros that pertain to library features with no success. I did at the option BOOST_NO_CXX11_CONSTEXPR and this doesn't work either. The compiler is the full clang 3.4 and does support c++11 features such as constexpr. It is the library that is old.

std::printf("GLIBCXX: %d\n",__GLIBCXX__);

produces

GLIBCXX: 20070514