Use cabal-helper for stack

Language/Haskell/GhcMod/Target.hs

@@ -149,7 +149,7 @@ targetGhcOptions crdl sefnmn = do
 
     case cradleProjectType crdl of
       CabalProject -> cabalOpts crdl
-      StackProject -> stackOpts crdl
+      StackProject -> cabalOpts crdl
       _ -> sandboxOpts crdl
  where
    zipMap f l = l `zip` (f `map` l)
@@ -266,17 +266,9 @@ packageGhcOptions = do
     crdl <- cradle
     case cradleProjectType crdl of
       CabalProject -> getGhcMergedPkgOptions
-      StackProject -> stackOpts crdl
+      StackProject -> getGhcMergedPkgOptions
       _ -> sandboxOpts crdl
 
-stackOpts :: MonadIO m => Cradle -> m [String]
-stackOpts crdl = do
-    pkgDbStack <- liftIO getStackPackageDbStack
-    let pkgOpts = ghcDbStackOpts pkgDbStack
-    return $ ["-i" ++ d | d <- [wdir,rdir]] ++ pkgOpts ++ ["-Wall"]
-  where
-    (wdir, rdir) = (cradleCurrentDir crdl, cradleRootDir crdl)
-
 -- also works for plain projects!
 sandboxOpts :: MonadIO m => Cradle -> m [String]
 sandboxOpts crdl = do