While renaming `networking.defaultMailServer` directly to
`services.ssmtp` is shorter and probably clearer, it causes eval errors
due to the second rename (directDelivery -> enable) when using e.g. `lib.mkForce`.
For instance,
``` nix
{ lib, ... }: {
networking.defaultMailServer = {
hostName = "localhost";
directDelivery = lib.mkForce true;
domain = "example.org";
};
}
```
would break with the following (rather confusing) error:
```
error: The option value `services.ssmtp.enable' in `/home/ma27/Projects/nixpkgs/nixos/modules/programs/ssmtp.nix' is not of type `boolean'.
(use '--show-trace' to show detailed location information)
```
NixOS 20.03 is built on kernel 5.4 and 19.09 is on 4.19, so we should update
this option to the highest value possible, per linked upstream instructions from
Amazon.
* nixos/nixpkgs.nix: Allow just using config in system
This assertion requires system to work properly. We might not have
this in cases where the user just sets config and wants Nixpkgs to
infer system from that. This adds a default for when this happens,
using doubleFromSystem.
* parens
`$toplevel/system` of a system closure with `x86_64` kernel and `i686` userland should contain "x86_64-linux".
If `$toplevel/system` contains "i686-linux", the closure will be run using `qemu-system-i386`, which is able to run `x86_64` kernel on most Intel CPU, but fails on AMD.
So this fix is for a rare case of `x86_64` kernel + `i686` userland + AMD CPU
Previously, systemd.network.links was only respected with networkd
enabled, but it's really udev taking care of links, no matter if
networkd is enabled or not.
With our module fixed, there's no need to manually manage the text file
anymore.
This was originally applied in 3d1079a20d,
but was reverted due to 1115959a8d causing
evaluation errors on hydra.
This mirrors the behaviour of systemd - It's udev that parses `.link`
files, not `systemd-networkd`.
This was originally applied in 36ef112a47,
but was reverted due to 1115959a8d causing
evaluation errors on hydra.
* Linkify all service options used in the code-examples.
* Demonstrated the use of `riot-web.override {}`.
* Moved the example how to configure a postgresql-database for
`matrix-synapse` to this document from the 20.03 release-notes.
Fixes some dependency ordering problems at boot time with services that
require DNS. Without Type=notify these services might be started before
stubby was ready to accept DNS requests.
