Failed to `Cargo doc` in the rust-std project

I cloned the rust-std project from github.com. When I use cargo doc command, It failed. How to resolve it? Thanks!

The Rust standard library requires a special build tool. You can read about it in the README.md, where it says the following:

If you’d like to build the documentation, it’s almost the same:

./x.py doc

The generated documentation will appear under doc in the build directory for
the ABI used. I.e., if the ABI was x86_64-pc-windows-msvc, the directory will be
build\x86_64-pc-windows-msvc\doc.