reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        git checkout f685204c57e87d2a88b159c7525426d70ee745c9
        b4 shazam https://lore.kernel.org/r/d3f47c9b5b08237b6e76f7b0739d59089683c86e.1747826775.git.jgh@exim.org
        # 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 net/ipv4/