cabal new-haddock --ghcjs fails to build

When building with ghcjs, haddock build fails. To reproduce use the following command in https://github.com/composewell/streamly repo:

```
cabal new-haddock --project-file cabal.project.ghcjs
```

This is the error produced ultimately:

```
Haddock's resource directory does not exist!

Warning: Failed to build documentation for streamly-0.6.0.
```

This same issue occurs when building the ghcjs compiler itself as well using `cabal new-build`. See ghcjs/ghcjs#653 .