RE: guix gc doesn't seem to clean old guix revision

[YOANN P]

> It is similar to Bug#36785 [1].

> As said, it is not a bug of "guix pull" but a bug of the
> configuration. Adding the root user to your Dockerfile should fix the
> issue you encounter.

The fact that guix require $USER to be set is IMO a kind of bug and is
documented anywhere.
It will be less prone to errors to relay for $USER on something like 
`whoami` and for $HOME expanding `~$USER`.

That say, finally, after setting $USER, and after restart the container before
doing `guix gc`, it seems far better: 1.0.1 ( 404Mo ) , latest ( 570Mo ).

So, not sure if it is normal, but it seems there is an overhead of 166Mo 
between the binary version and after doing 'guix pull' and 'guix gc'.

Best regards,