reproduce (this is a W=1 build):
        # https://github.com/nbdd0121/linux/commit/d12fb6412e5338bb69eab42f45ede455a57fbfbf
        git remote add nbdd0121 https://github.com/nbdd0121/linux
        git fetch --no-tags nbdd0121 io_projection
        git checkout d12fb6412e5338bb69eab42f45ede455a57fbfbf

        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash CLIPPY=1 rustdoc