This doesn't fix anything yet but maybe running non-ancient versions will make
it easier to fix something.

Got it to compile!
This could be chinese for all I know.

The author of the library used says the tests currently fail.
This might be a problem with how Nix handles things.

Also, client-side quantile computation is not available
anymore.  We'll just user server-computed histograms instead.

We can't control whether Stripe puts the voucher we supply in its metadata.
We can control whether we put the Stripe ChargeId Stripe supplies in our
database, though.

The new stanza is the automatic result.

And various associated changes necessary to keep the build working

This avoids needless build churn and potentially destabilizing changes from
upstream (though the latter does not seem likely since upstream changes should
not affect packages in our resolver, only newer resolvers).