reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git/commit/?id=810b8b6c4e02c40991c29491cec09ebdaf5ec6d0
        git remote add geert-renesas-drivers https://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git
        git fetch --no-tags geert-renesas-drivers renesas-clk-for-v7.4
        git checkout 810b8b6c4e02c40991c29491cec09ebdaf5ec6d0

        # 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