Allow for XDG_CONFIG_HOME on darwin (macOS)

[jcrben]

At some point I expect to open a PR to update this, but would appreciate some reassurance that it would be well-received.

Specifically, I would like to update

autojump-rs/src/config/mod.rs

Line 48 in 0ddb11f

let mut tmp = home_dir();

to accept an environment variable specifying the location.

Ideally, it would use XDG_CONFIG_HOME on darwin - a number of utilities on the platform respect XDG_CONFIG_HOME.

When I can't set this environment variable, I use symlinks to put the file in my typical place (i.e., my dotfiles repo), which I incrementally backup with a borgbackup cron job and version some files (altho prolly not this one). In this case, I noticed that I wasn't able to set up a symlink from my dotfiles to the destination - my symlink kept getting clobbered.

[xen0n]

I investigated this when I first saw the issue but quickly got overwhelmed by Real Life:tm:. It's Chinese holiday season soon and I'll consider this in a few days.

[jonhoo]

The easiest way to achieve this in a super nice way is to use a crate like dirs (or the slightly higher-level directories) which handles all the platform-specific tweaks for you!

[xen0n]

Moving to $XDG_CONFIG_HOME will need some migration logic in place, and that's gonna require some serious testing to avoid breaking people's installations. Currently there's no integration test written and that's why the issue is not solved 1 year later. Sorry for the radio silence on this!

Currently the CI infra based on trust is also outdated. So I plan to first address the CI issue and cut a new release, then proceed to work on this issue.