Customization ctests now failing on master

[Jürgen Spitzmüller]

Am Samstag, dem 12.08.2023 um 12:47 +0200 schrieb Jürgen Spitzmüller:
> > Another possible patch attached
> 
> Yes, this is neat, but I wanted to avoid changing the package loading
> order if not absolutely necessary.

I came back to this because I like its simplicity and went ahead
implementing a variant that maintains the loading order.

-- 
Jürgen