reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # install powerpc cross compiling tool for clang build
        # apt-get install binutils-powerpc64le-linux-gnu
        git remote add powerpc https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git
        git fetch powerpc next
        git checkout powerpc/next
        b4 shazam https://lore.kernel.org/r/9D8FEE1731685D9B+20240102024834.1276-2-luming.yu@shingroup.cn
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash