reproduce (this is a W=1 build):
        # https://github.com/stephensmalley/selinux-kernel/commit/04731499aa0dc2b500ec1c264986b40637ef49cd
        git remote add ssmalley-selinuxns https://github.com/stephensmalley/selinux-kernel
        git fetch --no-tags ssmalley-selinuxns working-selinuxns
        git checkout 04731499aa0dc2b500ec1c264986b40637ef49cd
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash security/selinux/