reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/commit/?id=f0de88303d5e7e04a1224bc7a00512b5a1c4fe7a
        git remote add net-next https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git
        git fetch --no-tags net-next main
        git checkout f0de88303d5e7e04a1224bc7a00512b5a1c4fe7a

        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=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash net/core/