reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://git.kernel.org/pub/scm/linux/kernel/git/jpoimboe/linux.git/commit/?id=62e666a6052abd6142d52405ea99e83ab7d48a83
        git remote add jpoimboe https://git.kernel.org/pub/scm/linux/kernel/git/jpoimboe/linux.git
        git fetch --no-tags jpoimboe klp-build-v1.5
        git checkout 62e666a6052abd6142d52405ea99e83ab7d48a83
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 prepare