reproduce (this is a W=1 build):
        # https://github.com/jimc/linux/commit/af718ee6a3256d73ee276d2c2bbbae9df0da6bfb
        git remote add jimc https://github.com/jimc/linux.git
        git fetch --no-tags jimc dyndbg-maple-clean
        git checkout af718ee6a3256d73ee276d2c2bbbae9df0da6bfb

        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=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc prepare