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
        # https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git/commit/?id=a07293862960e1329b45044916498891ed8161a1
        git remote add arnd-asm-generic https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git
        git fetch --no-tags arnd-asm-generic syscall-tbl-6.9
        git checkout a07293862960e1329b45044916498891ed8161a1
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-17 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=um olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-17 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=um prepare