mkdirp, but chown to the owner of the containing
folder if possible and necessary.
That is, on Windows and when running as non-root, it's exactly the same as
mkdirp.
When running as root on non-Windows systems, it uses
infer-owner to find the owner of the
containing folder, and then chownr to set the
ownership of the created folder to that same uid/gid.
This is used by npm to prevent root-owned files and
folders from showing up in your home directory (either in node_modules or
in the ~/.npm cache) when running as root.