Add cabal-helper for decoding Cabal-1.22 setup-configs

.. without having to worry about Cabal version conflicts

src/GHCModCabal.hs

@@ -0,0 +1,28 @@
+{-# LANGUAGE BangPatterns #-}
+module Main where
+
+import Control.Applicative
+
+import Distribution.Simple.Utils (cabalVersion)
+import Distribution.Simple.Configure
+import Distribution.Text ( display )
+import System.Environment
+import System.Directory
+
+main :: IO ()
+main = do
+  args <- getArgs
+  case args of
+    "version":[] -> do
+        putStrLn $ "using version " ++ display cabalVersion ++ " of the Cabal library"
+    "print-setup-config":args' -> do
+        mfile <- findFile ["dist"] "setup-config"
+
+        let file = case mfile of
+                     Just f -> f
+                     Nothing -> let !(f:[]) = args' in f
+
+        putStrLn =<< show <$> getConfigStateFile file
+
+    cmd:_ -> error $ "Unknown command: " ++ cmd
+    [] -> error "No command given"