[boost] [Config] BOOST_HAS_PTHREAD_MUTEXATTR_SETTYPE not defined in MACOS for GCC-5

Hi John, I'm having an issue with gcc-5.1 on MacOs. BOOST_HAS_PTHREAD_MUTEXATTR_SETTYPE is not defined. I see that there are things like #if __MACH__ && !defined(_MSL_USING_MSL_C) ... # if (__GNUC__ == 4) // Both gcc and intel require these. # define BOOST_HAS_PTHREAD_MUTEXATTR_SETTYPE # define BOOST_HAS_NANOSLEEP # endif #else ... // BOOST_HAS_PTHREAD_MUTEXATTR_SETTYPE not defined here #endif Wondering why the GCC version must be 4 and why when _MSL_USING_MSL_C is defined these PTHREAD attributes are not defined neither. BTW, when I compile with version 4 everything works correctly. Vicente