reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/brauner/linux/commit/bcd0b5f0199b33d65271c10859b414b4864aa1f2
        git remote add brauner-github https://github.com/brauner/linux.git
        git fetch --no-tags brauner-github vfs-6.18.rust
        git checkout bcd0b5f0199b33d65271c10859b414b4864aa1f2
        # 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 prepare