reproduce (this is a W=1 build):
        # https://github.com/KanjiMonster/linux/commit/70fb214830ff40f92fbfbacf66223b3cd3e803b9
        git remote add kanjimonster https://github.com/KanjiMonster/linux
        git fetch --no-tags kanjimonster b53/wip
        git checkout 70fb214830ff40f92fbfbacf66223b3cd3e803b9

        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=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/net/dsa/b53/