reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu.git/commit/?id=eb0c2bf59aeda4481f69d166a3014c9ea4865229
        git remote add gerg-m68knommu https://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu.git
        git fetch --no-tags gerg-m68knommu dt
        git checkout eb0c2bf59aeda4481f69d166a3014c9ea4865229

        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # apt-get install sparse
        # sparse version: v0.6.4-71-g610d841d

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-14.3.0 ~/lkp-tests/kbuild/make.cross W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=m68k olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-14.3.0 ~/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=m68k SHELL=/bin/bash drivers/tty/serial/