reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm.git/commit/?id=43924f2f76b8bdef22a20256d969dca66a9bf3ef
        git remote add pcmoore-lsm https://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm.git
        git fetch --no-tags pcmoore-lsm working-lsm_init_rework
        git checkout 43924f2f76b8bdef22a20256d969dca66a9bf3ef
        # apt-get install sparse
        # sparse version: v0.6.4-66-g0196afe1
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=x86_64 olddefconfig
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__ -fmax-errors=unlimited -fmax-warnings=unlimited' O=build_dir ARCH=x86_64 SHELL=/bin/bash security/