From-scratch clone/build fails on `src/ftxui_sample/CMakeFiles/intro.dir/main.cpp.obj`

*Note: I also encountered [this issue](https://github.com/cpp-best-practices/cmake_template/issues/138), but it already has an issue which includes a fix, so I've elided it here.*

Running on Windows 10.

# Configure/generate the `clang Debug` CMake preset.
- Using Ninja as the generator; not explicitly listed in `README_building.md`, but `README_dependencies.md` specifically shows it in the example command, so I assume it's supposed to work.
- Several warnings:

- I've changed no configuration options.
- I installed `vcvarsall.bat` with `setup-cpp`. It's not on PATH, possibly that's a problem?
- No idea what the `test/constexpr_tests.cpp` thing is about.

# Run `cmake --build ./out\build\windows-clang-debug`.
- *Not* `cmake --build ./build`, which is what `README_building.md` currently says; that seems to be out of date with the CMake presets.
- Warning in `fmt\base.h` and `src\format.cc`.

- Failure on `src/ftxui_sample/CMakeFiles/intro.dir/main.cpp.obj`. No meaningful output given?

- Further warnings in `spdlog`. These don't look too bad.