In C++20, std::filesystem::path::u8string() returns std::u8string,
which armips assigns to std::string. Its own CMake build pins C++17;
do the same in the Visual Studio projects, the legacy Android build and
libretro (as a separate module in libretro's Android.mk, which has no
per-file flags).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>