Use SOURCE_DATE_EPOCH with GNU install

[Ludovic Courtès]

"Chris Lamb" <chris at reproducible-builds.org> skribis:

> Ludovic Courtès wroteP
>
>> > │ - Birth: 2020-07-20 09:02:11.688603176 +0000
>> > │ + Birth: 2020-07-20 08:47:51.046971751 +0000
>> 
>> As you can see above, Nix resets the modification time (“mtime”) of
>> installed files to the Epoch plus one second.
>> 
>> The creation time reported as “Birth” is an extension, not reported by
>> stat(2), but fortunately it’s a piece of information that’s generally
>> not used.
>> 
>> Perhaps diffoscope should omit the creation time by default?
>
> It has done so since version 146, released in May 2020:
>
>   https://diffoscope.org/news/diffoscope-146-released/

Nice, thank you!

Ludo’.