diff --git a/gf.cabal b/gf.cabal
index cf36106a3..3e823f26e 100644
--- a/gf.cabal
+++ b/gf.cabal
@@ -159,7 +159,12 @@ Executable gf
 --if flag(new-comp)
 --  cpp-options: -DNEW_COMP
 
-  build-tools: happy, alex>=3
+  build-tools: happy
+
+  if impl(ghc>=7.8)
+    build-tools: happy>=1.19, alex>=3.1
+  else
+    build-tools: happy, alex>=3
 
   if os(windows)
     build-depends: Win32
diff --git a/src/binary/Data/Binary/Builder.hs b/src/binary/Data/Binary/Builder.hs
index 183483945..6aee97964 100644
--- a/src/binary/Data/Binary/Builder.hs
+++ b/src/binary/Data/Binary/Builder.hs
@@ -55,6 +55,7 @@ module Data.Binary.Builder (
   ) where
 
 import Foreign
+import System.IO.Unsafe(unsafePerformIO)
 import Data.Monoid
 --import Data.Word
 import qualified Data.ByteString      as S
diff --git a/src/binary/Data/Binary/Get.hs b/src/binary/Data/Binary/Get.hs
index c2c43b691..0a2f12117 100644
--- a/src/binary/Data/Binary/Get.hs
+++ b/src/binary/Data/Binary/Get.hs
@@ -89,6 +89,9 @@ import Control.Applicative (Applicative(..))
 import Foreign
 
 -- used by splitAtST
+#if MIN_VERSION_base(4,6,0)
+import Control.Monad.ST.Unsafe(unsafeInterleaveST)
+#endif
 import Control.Monad.ST
 import Data.STRef