Refactor test filtering

Author: hamishmack

test/githash/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, lib, haskell-nix, recurseIntoAttrs, testSrc, compiler-nix-name, runCommand, gitMinimal, buildPackages }:
+{ stdenv, lib, haskell-nix, haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name, runCommand, gitMinimal, buildPackages }:
 
 with lib;
 
@@ -44,7 +44,7 @@ let
 in recurseIntoAttrs {
   # githash runs git from TH code and this needs a cross compiled git exe
   # to work correctly.  Cross compiling git is currently brocken.
-  meta.disabled = compiler-nix-name == "ghc901" || pkgs.haskell-nix.haskellLib.isCrossHost;
+  meta.disabled = compiler-nix-name == "ghc901" || haskellLib.isCrossHost;
 
   ifdInputs = {
     inherit (project) plan-nix;