reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git/commit/?id=b49bbb5dbe7654f0d7996206f543d91bbed33569
        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 master
        git checkout b49bbb5dbe7654f0d7996206f543d91bbed33569
        # 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 SHELL=/bin/bash drivers/gpu/drm/bridge/