ubuntu 16.04 编译matconvnet gcc版本过高问题

cd /usr/local/MATLAB/R2016b/sys/os/glnxa64  #where I installed my matlab
sudo mv libstdc++.so.6.0.20 bak-libstdc++.so.6.0.20
sudo mv libstdc++.so.6 bak-libstdc++.so.6
sudo ln -sf /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21 ./
sudo ln -sf ./libstdc++.so.6.0.21 ./libstdc++.so.6