A library file for the Haskell compiler ghc

...4.

This replaces my previous request for a "haskell" library file.
I think it is better to have separate Dockerfiles for the base Haskell compiler ghc and the Haskell Platform.
These don't have version numbers which are at all well related or move in lock step.
Furthermore, people will want specify the "latest" for either e.g.

```
FROM ghc:latest
```

or

```
FROM haskell:latest
```

so I think this requires separate library files.

Thank you!