Just fixing up path_view with the feedback from SG16 and LEWG right now. Does anybody have to hand a char8_t implementation for C++ 14? I've currently got a hacky substitute which is really char, but I'd like something better, if somebody already has implemented char_traits et al for older C++.
With both gcc (9.1) and Clang (7, 8) you can enable char8_t with the '-fchar8_t' option for earlier standard modes. I'm not sure that is helpful for your use case though.
If you can't use the '-fchar8_t' option, then you have two options: