reproduce (this is a W=1 build):
        git remote add drm-tip https://gitlab.freedesktop.org/drm/tip.git
        git fetch drm-tip drm-tip
        git checkout drm-tip/drm-tip
        b4 shazam https://lore.kernel.org/r/20251212143504.973839-25-dev@lankhorst.se

        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/gpu/drm/ttm/tests/