:construction_worker: trying to use libstdc++
:construction_worker: trying to use libstdc++

https://github.com/travis-ci/apt-source-whitelist/issues/372#issuecomment-320547215

kaidokert/json,nlohmann/json,nlohmann/json,kaidokert/json,kaidokert/json,nlohmann/json,theodelrieu/json,theodelrieu/json