opensmtpd: 5.4.5p1 -> 5.7.1p1

[gebner]

OpenSMTPD now supports external filters, which are distributed in a separate opensmtpd-extras package, and usually installed as binaries in /usr/libexec/opensmtpd/filter-*. However they don't work with our package yet since OpenSMTPD looks for them in /nix/store/*-opensmtpd-5.7.1p1/libexec/opensmtpd/, where you can't install them:

    if (asprintf(&path, "%s/filter-%s", PATH_LIBEXEC, prog) == -1) {

Any ideas on how to fix that? Look in /run/current-system/sw/libexec? Add an environment variable?

[the-kenny]

One common solution is patch it for an environment variable, then provide a wrapper-function opensmtp-with-filters or similar that allows you to declaratively specify filters in a build.

[gebner]

Okay, now we patch opensmtpd to read the environment variable OPENSMTPD_PROC_PATH and, if set, look there instead of /nix/store/...-opensmtpd-5.7.1p1/libexec/opensmtpd for the filters.

The nixos module then takes an extra option for the packages that contain filters (no default due to #10039), and passes that as an environment variable to the smtpd daemon.

[gebner]

Now extras are packaged with all dependencies enabled.

[lucabrunox]

Awesome work!

Please check the travis failure. Make sure you enable chroot builds when building packages.

[gebner]

I'm on NixOS, and it works with or without chroot enabled. I have now added the path to libevent to the configure flags, as the was the library which was used from /usr/lib. I hope that this was the only impure reference.

[lucabrunox]

Travis passed thanks.