reproduce (this is a W=1 build):
        # https://github.com/jimc/linux/commit/fce78b7f456f7e2c306de600ea603e2017c4f2d5
        git remote add jimc https://github.com/jimc/linux.git
        git fetch --no-tags jimc dd-classmaps-v9-akpm
        git checkout fce78b7f456f7e2c306de600ea603e2017c4f2d5

        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # apt-get install sparse
        # sparse: v0.6.5-rc1

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-15.2.0 ~/lkp-tests/kbuild/make.cross W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=microblaze olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-15.2.0 ~/lkp-tests/kbuild/make.cross W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=microblaze SHELL=/bin/bash lib/