C++17ification!
- Filesystem interaction now uses std::filesystem::path.
- Usage of const char*, std::string have been changed to
std::string_view where appropriate.
- Usage of printf-style functions changed to use fmt.
This seems to dramatically improve most games (especially with
--vsync=false), though it may cause swap issues with others.
New code should be easier to port, and enables elemental-forms to be
drawn for any emulator UI.
