reproduce (this is a W=1 build):
        git checkout v7.0-rc3
        b4 shazam https://lore.kernel.org/r/56dd1a892279fade2292b7eef7a52112901ae2fd.1773770778.git.chleroy@kernel.org

        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=$HOME/0day COMPILER=gcc-15.2.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-15.2.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc prepare