[FR] Search on user's dunstrc.d, even if no dunstrc found

[pataquets]

Issue description

As I'm tuning my dunstrc config, I'd like to just use dunstrc.d/*.conf files and just use the installed, default dustrc file as basis.
However, I've found that placing my dunstrc.d dir in my ~/.config/ dir, without a matching ~/.config/dunstrc file, causes the .d dir to be ignored. As soon as I copy the default-installed dunstrc file to my home config, overrides work.

I'd like to just have the .d/*.conf files in my config dir and get the base defaults from the installed files, so I don't have to track the base dunstrc config defaults from version to version.

Installation info

• Version: v1.9.2-14-g2cd719a
• Install type: built from source
• Window manager / Desktop environment: i3 (X11, from repos)
• Distro: Ubuntu Jammy

[fwsmit]

Possible solutions are using /etc/dunstrc.d/.conf or creating an empty ~/.config/dunstrc.