filesystem: move to using std::filesystem after C++17 switch old compilers will croak compiling this, but it's not like we *really* need to support them (they probably croak compiling Qt as well)

#ifndef __sys__osx__filesystem_h
#define __sys__osx__filesystem_h

#include <string>

namespace osx {

std::string GetApplicationSupportDirectory();

}

#endif // __sys__osx__filesystem_h