reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # install um cross compiling tool for clang build
        # apt-get install binutils-um-linux-gnu
        git checkout 91e21479c81dd4e9e22a78d7446f92f6b96a7284
        b4 shazam https://lore.kernel.org/r/20241023-drm-vc4-2712-support-v1-11-1cc2d5594907@raspberrypi.com
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=um olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=um SHELL=/bin/bash drivers/gpu/drm/vc4/ kernel/bpf/