reproduce (this is a W=1 build):
        # https://github.com/zen-kernel/zen-kernel/commit/f3e8d2abb7fb9e5202ac3cb9991bd7aad83c9aee
        git remote add zen https://github.com/zen-kernel/zen-kernel
        git fetch --no-tags zen 7.1/prjc
        git checkout f3e8d2abb7fb9e5202ac3cb9991bd7aad83c9aee

        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=$HOME/0day COMPILER=gcc-16.1.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-16.1.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash kernel/