reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        git remote add shuah-kselftest https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git
        git fetch shuah-kselftest kunit
        git checkout shuah-kselftest/kunit
        b4 shazam https://lore.kernel.org/r/20240508132557.599213-1-ivan.orlov0322@gmail.com
        # 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 SHELL=/bin/bash