reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/stephensmalley/selinux-kernel/commit/66c448df995fb8d6c5c9a4875efc0ab56a5dd21d
        git remote add ssmalley-selinuxns https://github.com/stephensmalley/selinux-kernel
        git fetch --no-tags ssmalley-selinuxns working-selinuxns
        git checkout 66c448df995fb8d6c5c9a4875efc0ab56a5dd21d
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=xtensa olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-8.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=xtensa SHELL=/bin/bash security/selinux/