Allow to build zlib and lzma statically

This should fix issues on Darwin.

3rdparty/zlib/test/Utils.hs

@@ -0,0 +1,28 @@
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+module Utils where
+
+import qualified Data.ByteString.Lazy as BL
+import qualified Data.ByteString      as BS
+
+import Test.QuickCheck
+
+-------------------
+-- QuickCheck Utils
+
+maxStrSize :: Double
+maxStrSize = 500
+
+-- convert a QC size parameter into one for generating long lists,
+-- growing inverse exponentially up to maxStrSize
+strSize :: Int -> Int
+strSize n = floor (maxStrSize * (1 - 2 ** (-fromIntegral n/100)))
+
+instance Arbitrary BL.ByteString where
+  arbitrary = sized $ \sz -> fmap BL.fromChunks $ listOf $ resize (sz `div` 2) arbitrary
+  shrink = map BL.pack . shrink . BL.unpack
+
+instance Arbitrary BS.ByteString where
+  arbitrary = sized $ \sz -> resize (strSize sz) $ fmap BS.pack $ listOf $ arbitrary
+  shrink = map BS.pack . shrink . BS.unpack
+
+