reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git/commit/?id=9c2f5b6eb8b7da05e13cde60c32e0a8b1f5873b0
        git remote add broonie-sound https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git
        git fetch --no-tags broonie-sound for-next
        git checkout 9c2f5b6eb8b7da05e13cde60c32e0a8b1f5873b0
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-13.2.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-13.2.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash