reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/zen-kernel/zen-kernel/commit/98c9b99c3d9351380be5a9660f7d64c3cd9aec38
        git remote add zen https://github.com/zen-kernel/zen-kernel
        git fetch --no-tags zen 6.6/zen-sauce
        git checkout 98c9b99c3d9351380be5a9660f7d64c3cd9aec38
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=hexagon olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-18 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash