reproduce (this is a W=1 build):
        # https://github.com/jgunthorpe/linux/commit/10635ad3ff26a0e94b4ab147ac32c63f9b7c42ff
        git remote add jgunthorpe https://github.com/jgunthorpe/linux
        git fetch --no-tags jgunthorpe for-borah
        git checkout 10635ad3ff26a0e94b4ab147ac32c63f9b7c42ff

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash