typedef/alias inside constexpr functions incompatibility

[malachib]

Under certain circumstances, usings/typedefs interfere with a constexpr function qualifying as a constexpr

Offenders: src/estd/internal/chrono/operators.hpp

It seems this usually is OK. However, platformio's present ESP32 Arduino compilations fail, so I presume it's an artifact of ~GCC 8 behavior.