Update to alpine 3.12.0 - Problems with Haskell

[perlpunk]

I'm trying to update the base images to alpine 3.12.0.
However, for the haskell libraries I get the following failures:
https://gist.github.com/perlpunk/86d8701d971bcb423b7d821954e4da52

So HsYAML and YAMLReference don't build, but for different reasons.
Anyone who knows haskell is invited to give me a hint what's going wrong :)
@hvr or @vijayphoenix maybe?

[perlpunk]

This is the install script: https://github.com/yaml/yaml-runtimes/blob/master/docker/haskell/utils/hs-build.sh

[perlpunk]

Related to the YAMLReference error

Text/Yaml/Reference.hs:711:3: error:
    ‘fail’ is not a (visible) method of class ‘Monad’

I found this issue:
haskell/hsc2hs#27
So probably this fix is not yet in alpine 3.12:

/ # hsc2hs --version
hsc2hs version 0.68.5
/ # ghc --version
The Glorious Glasgow Haskell Compilation System, version 8.8.3