reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl.git/commit/?id=9582b6a47ef87168a3a57084f75fd7239a6c56f6
        git remote add cxl https://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl.git
        git fetch --no-tags cxl next
        git checkout 9582b6a47ef87168a3a57084f75fd7239a6c56f6

        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