Part 4, always got errors to run make -j4 command: /root/tmp/eos/libraries/fc/include/fc/utility.hpp:63:3: error: body of constexpr function ‘constexpr std::size_t fc::const_strlen(const char*)’ not a return-statement

Any ideas? my gcc version is 4.8.5, seems I have to upgrade gcc with higher version, right?