user_runtime_dir for *BSD

[ThomasWaldmann]

completely broken, returns invalid directory, see there:

borgbackup/borg#7638

when fixing this, make sure it works for root and for other users, see also: #188

[RayyanAnsari]

Some notes:

https://github.com/platformdirs/platformdirs/blob/50e638eec6cadee0dfe47197464241be8a70718d/src/platformdirs/unix.py#L150-L152

In Linux, /run was introduced with FHS 3.0, replacing /var/run (which still exists as a symlink for back compat). See FHS 3.0: /var/run and FHS 3.0: /run. The /run/user/$uid directory is created by pam_systemd, which also sets $XDG_RUNTIME_DIR (not sure about what OpenRC does).

On FreeBSD, the /run directory does not exist, instead using /var/run. See FreeBSD: hier(7). There is a package named pam_xdg that creates a runtime directory somewhere (I'm not exactly sure where, haven't tried it myself), and sets $XDG_RUNTIME_DIR. However this is not installed by default and there are no packages that are dependent on it. See FreeBSD: pam_xdg(8).
I have also not seen this package on other BSDs.

[ofek]

Would you be open to contributing a fix? We would gladly accept and release shortly after.

[gaborbernat]

#201 fixed this