Remove source filtering

This reverts #57, and resolves #88.

haskell-project.nix

@@ -35,19 +35,11 @@ in
       localPackagesOverlay = self: _:
         let
           fromSdist = self.buildFromCabalSdist or (builtins.trace "Your version of Nixpkgs does not support hs.buildFromCabalSdist yet." (pkg: pkg));
-          filterSrc = name: src: lib.cleanSourceWith { inherit src name; filter = path: type: true; };
         in
         lib.mapAttrs
           (name: value:
-            let
-              # callCabal2nix does not need a filtered source. It will
-              # only pick out the cabal and/or hpack file.
-              pkgProto = self.callCabal2nix name value.root { };
-              pkgFiltered = pkgs.haskell.lib.overrideSrc pkgProto {
-                src = filterSrc name value.root;
-              };
-            in
-            fromSdist pkgFiltered)
+            fromSdist (self.callCabal2nix name value.root { })
+          )
           config.packages;
 
       defaultBuildTools = hp: with hp; {