To make sure the patch doesn't break "guix pull", I've begun testing
using "guix time-machine" to go to an older version of Guix and then go
to the latest version of Guix (with the patch applied).

Older commits tested so far:

  * 1.3.0

    # 1.3.0 --> master + the patch applied
    guix time-machine --url=$PWD --commit=a0178d34f582b50e9bdbb0403943129ae5b560ff -- time-machine --url=$PWD --commit=47ffd21fa177e300df5346f275da1759870540b3 --disable-authentication -- describe

    (succeeds!)

1.3.0 is not a good test though because it's relatively recent, I'll
try some older versions as well.