undefined reference to `__sync_synchronize'

[fedor_qd]

I build c++ app without libstdc++ and with -nostdinc -std=c++14 options. stdlib not used, compiled with libsupc and libstdc++. My  GCC 6.1.0.
Is it bug?

Always yours, Strizhniou Fiodar
Всегда ваш, Стрижнёв Фёдор