haskell-diagrams: Don't invoke haddock.

This package is only a metapackage and doesn't contain any source files, so we
don't need to generate source code documentation at all.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Acked-by: Peter Simons <simons@cryp.to>

pkgs/development/libraries/haskell/diagrams/default.nix

@@ -5,6 +5,7 @@ cabal.mkDerivation (self: {
   version = "0.5";
   sha256 = "163h2fg3gpmsfm57gjyja2rxh9pl6s3xnzlidfdy201zbk1mzdg5";
   buildDepends = [ diagramsCairo diagramsCore diagramsLib ];
+  noHaddock = true;
   meta = {
     homepage = "http://projects.haskell.org/diagrams";
     description = "Embedded domain-specific language for declarative vector graphics";