reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # install powerpc cross compiling tool for clang build
        # apt-get install binutils-powerpc64-linux-gnu
        # https://github.com/nunojsa/linux/commit/56a0faf5df7548936623a26c728ff3f0e970ef6a
        git remote add nsa https://github.com/nunojsa/linux
        git fetch --no-tags nsa dev/iio-backend-axi-dds-test
        git checkout 56a0faf5df7548936623a26c728ff3f0e970ef6a
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-19 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-19 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash drivers/iio/dac/