reproduce (this is a W=1 build):
        # https://github.com/morimoto/linux/commit/57dce640516332444cd0930a853c65c9fe36e2ee
        git remote add morimoto https://github.com/morimoto/linux
        git fetch --no-tags morimoto string-helper-2025-11-13
        git checkout 57dce640516332444cd0930a853c65c9fe36e2ee

        # install powerpc cross compiling tool for clang build
        # apt-get install binutils-powerpc-linux-gnu
        # clang-22 might not be officially released. Try a lower version if installation fails.
        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=$HOME/0day COMPILER=clang-22 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-22 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash drivers/gpu/drm/panel/