minor testcases fix

[zoranbosnjak]

• some build warnings fixed
• fix build problem under 'nix' environment

[zoranbosnjak]

@myroslambda @keera-studios-admin
Is this project maintained?
It is marked "broken" in the nix packages. I belive that this pull request would fixed the nix-build problem. Please consider merging it to the upstream.

[myroslambda]

It is, but the fix is incomplete.

These haddock tests are all over the place, so more than just these two would have to change. We need to create two separate issues (one for the warnings and one for the haddock command invocation) and apply the fixes independently.

I do not understand why calling haddock directly without providing some context or a package DB will work. How does haddock know where to look for existing packages?

[myroslambda]

I have created both issues (#96, #97). I will close this PR and we will address those independently. I will point to this PR from both. We can continue the discussion there.

Thanks for the PR and for bringing my attention to this.