https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103949
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Note in newer versions of glibc, libpthread is all intergrated into libc and there is no issues again. For Mac OS X/darwin you don't need -lm -pthread because libc has it. >gcc libstdc++ implements std::thread. So what's your point again? Because it implements it on top of pthreads. While C threads is implemented inside the libc. I still think this should not be done on the GCC side as it is changing/fixing on the glibc side of things already.