reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/jcmvbkbc/linux-xtensa/commit/a5c85057774730482c8e4ece98a1358656d82304
        git remote add jcmvbkbc-xtensa https://github.com/jcmvbkbc/linux-xtensa
        git fetch --no-tags jcmvbkbc-xtensa xtensa-6.8-rc2-esp32
        git checkout a5c85057774730482c8e4ece98a1358656d82304
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-13.2.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=sparc64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-13.2.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=sparc64 SHELL=/bin/bash