XDG_CONFIG_HOME ignored

[noiioiu]

Problem

Running beet with XDG_CONFIG_HOME set:

$ export $XDG_CONFIG_HOME=~/etc
$ beet

results in a config directory being created under ~/.config, instead of the correct location, ~/etc.
If there is a text file named ~/.config/beets, beet crashes with the following error message:

error: database file /home/username/.config/beets/library.db cannot not be opened: unable to open database file

(Also, library.db should probably be in a different base directory, but that is a separate issue).

Setup

• OS: OpenBSD 7.6 and NixOS 24.05 (but should be reproducible on any Unix-like system)
• Python version: 3.11.9
• beets version: 1.6.0
• Turning off plugins made problem go away (yes/no): no
• Configuration: none/default (but shouldn't matter)

This may actually be a bug in confuse rather than in beets. Beet seems to work correctly with a patched confuse.