reproduce (this is a W=1 build):
        git remote add rust https://github.com/Rust-for-Linux/linux
        git fetch rust rust-next
        git checkout rust/rust-next
        b4 shazam https://lore.kernel.org/r/010001958dfeb4c7-0ed042d2-613b-4023-bb91-0c64f8a84fc9-000000@email.amazonses.com
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash CLIPPY=1 rustdoc