reproduce (this is a W=1 build):
        # https://github.com/norov/linux/commit/6f976707ef5fdb55383287e3a0960eadefda5184
        git remote add norov https://github.com/norov/linux
        git fetch --no-tags norov compat_get_cpumask
        git checkout 6f976707ef5fdb55383287e3a0960eadefda5184
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 prepare