reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/commit/?id=a74a57773d43d87ab4cc8ac4fdfa0fa511e43da6
        git remote add kees https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git
        git fetch --no-tags kees for-next/kspp
        git checkout a74a57773d43d87ab4cc8ac4fdfa0fa511e43da6

        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