reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/niks/linux.git/commit/?id=0cc26afe6244fe307926528550a4de09c1e5846e
        git remote add niks https://git.kernel.org/pub/scm/linux/kernel/git/niks/linux.git
        git fetch --no-tags niks has_ioport_v6
        git checkout 0cc26afe6244fe307926528550a4de09c1e5846e
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=um olddefconfig
        make W=1 O=build_dir ARCH=um SHELL=/bin/bash lib/