cmake/nc_cxx_stdcxxfs.cpp

#include <filesystem>
#include <iostream>

int
main (int argc, char **argv)
{
    (void)argc;
    (void)argv;

    // Instantiating a path isn't enough for clang. We need to call a method
    // implemented in the external library; like 'stem'.
    std::filesystem::path p { "foo" };
    std::cout << p.stem () << '\n';
    return 0;
}