reproduce (this is a W=1 build):
        # https://github.com/cschaufler/smack-next/commit/ecd4785c2969ce0994fd9752ceeade2181b8ef34
        git remote add cschaufler-smack-next https://github.com/cschaufler/smack-next
        git fetch --no-tags cschaufler-smack-next pr/2
        git checkout ecd4785c2969ce0994fd9752ceeade2181b8ef34

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash