f you use the 
% latest gcc/g++ with MATLAB 2020a or earlier. One  alternative is to install 
% the supported compiler of the MATLAB version  in use (see <https://www.mathworks.com/support/requirements/previous-releases.html 
% here>) and then re-run |install_mex| (the supported compiler is used if available). 
% Alternatively, you can try one of solutions presented <https://www.mathworks.com/matlabcentral/answers/329796-issue-with-libstdc-so-6 
% here> or try the precompiled mex-files from <https://github.