Hi! Building with milter protocol support was broken in gross 1.0.2. I've fixed it in version 1.0.3[1], however it remains untested and disabled by default. If the package maintainer decide to enable it when updating the package, this can be done with the --enable-milter configure flag.
NB: don't update to 1.0.3, the 1.0.4 version with important bugfix will be released very soon. [1]: https://codeberg.org/bizdelnick/gross/releases -- Regards, Dmitry Mikhirev
