treesum: when walking: if filenames contain CR and/or LF pretend that this names are not properly encoded. So the alt_xxx() path is to be used with a proper additional backslash encoding. Also the directory is marked tainted.

# Pure-Python-Build
[build-system]
requires = ["setuptools>=43.0", "wheel>=0.33"]
build-backend = "setuptools.build_meta"