This is necessary for VPNs where some of the nodes run pre-1.1 versions.
Most of Linux distros [0] and even the nixpkgs.tinc attribute run on that
version, so it might be useful to have that option.
[0] https://repology.org/project/tinc/versions
This allows configuring IP addresses on a tinc interface using
networking.interfaces."tinc.${n}".ipv[46].addresses.
Previously, this would fail with timeouts, because of the dependency
chain
tinc.${netname}.service
--after--> network.target
--after--> network-addresses-tinc.${n}.service (and network-link-…)
--after--> sys-subsystem-net-devices-tinc.${n}.device
But the network interface doesn't exist until tinc creates it! So
systemd waits in vain for the interface to appear, and by then the
network-addresses-* and network-link-* units have failed. This leads
to the network link not being brought up and the network addresses not
being assigned, which in turn stops tinc from actually working.
This breaks with networking backends enabled and
also creates large delays on boot when some services depends
on the network target. It is also not really required
because tinc does create those interfaces itself.
fixes#27070
```Tinc```'s pid file has more info than just a pid
```
# cat /run/tinc.dmz.pid
12209 7BD4A657B4A04364D268D188A0F4AA972A05247D802149246BBE1F1E689CABA1 127.0.0.1 port 656
```
so ```systemd``` fails to parse it.
It results in long (re)start times when ```systemd``` waits for a correct pid file to appear.
* tinc: Mention in docs that the host name may not be used verbatim.
Source:
5c344f2976/src/net_setup.c (L341)
* tinc: also replaces non-alphanumeric characters.
- add missing types in module definitions
- add missing 'defaultText' in module definitions
- wrap example with 'literalExample' where necessary in module definitions
