Backports an old version of the Elm language (before the release where
they made everyone rewrite their programs), from the same old nixpkgs
commit as was previously used in overrides (see CL/2646).
Change-Id: I0ae4cc611aa40269b290651ab982c1db93518d8a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2649
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
