diff --git a/jack.cabal b/jack.cabal
--- a/jack.cabal
+++ b/jack.cabal
@@ -1,5 +1,5 @@
 Name:               jack
-Version:            0.6.1
+Version:            0.6.1.1
 License:            GPL
 License-File:       LICENSE
 Author:             Soenke Hahn, Henning Thielemann
@@ -10,7 +10,8 @@
 Category:           Sound
 Build-Type:         Simple
 Cabal-Version:      >=1.6
-Tested-With:        GHC == 6.8.2, GHC == 6.10.4, GHC == 6.12.3, GHC == 7.0.2, GHC == 7.2.1
+Tested-With:        GHC==6.8.2, GHC==6.10.4, GHC==6.12.3
+Tested-With:        GHC==7.0.2, GHC==7.2.1, GHC==7.4.1
 Extra-Source-Files:
   README
   INSTALL
@@ -22,7 +23,7 @@
 Source-Repository this
   type:     darcs
   location: http://code.haskell.org/jack/
-  tag:      0.6.1
+  tag:      0.6.1.1
 
 Flag buildExamples
   description: Build example executables
@@ -49,7 +50,7 @@
     Sound.JACK.FFI.MIDI
   Build-Tools:        c2hs>=0.15.1
   Hs-Source-Dirs:     src
-  GHC-Options:        -threaded -Wall -fwarn-tabs -fwarn-incomplete-record-updates
+  GHC-Options:        -Wall -fwarn-tabs -fwarn-incomplete-record-updates
   If impl(ghc >= 6.12)
     GHC-Options:      -fwarn-unused-do-bind
   If os(darwin)
@@ -70,7 +71,7 @@
 Executable amplify
   If !flag(buildExamples)
     Buildable: False
-  GHC-Options:        -threaded -Wall -fwarn-tabs -fwarn-incomplete-record-updates
+  GHC-Options:        -Wall -fwarn-tabs -fwarn-incomplete-record-updates
   Extensions:         ForeignFunctionInterface
   Extra-Libraries:    jack
   Other-Modules:      Sound.JACK.FFI.MIDI
@@ -80,7 +81,7 @@
 Executable impulse-train
   If !flag(buildExamples)
     Buildable: False
-  GHC-Options:        -threaded -Wall -fwarn-tabs -fwarn-incomplete-record-updates
+  GHC-Options:        -Wall -fwarn-tabs -fwarn-incomplete-record-updates
   Extensions:         ForeignFunctionInterface
   Extra-Libraries:    jack
   Other-Modules:      Sound.JACK.FFI.MIDI
@@ -90,7 +91,7 @@
 Executable midimon
   If !flag(buildExamples)
     Buildable: False
-  GHC-Options:        -threaded -Wall -fwarn-tabs -fwarn-incomplete-record-updates
+  GHC-Options:        -Wall -fwarn-tabs -fwarn-incomplete-record-updates
   Extensions:         ForeignFunctionInterface
   Extra-Libraries:    jack
   Other-Modules:      Sound.JACK.FFI.MIDI
diff --git a/src/Sound/JACK.hs b/src/Sound/JACK.hs
--- a/src/Sound/JACK.hs
+++ b/src/Sound/JACK.hs
@@ -81,6 +81,7 @@
 
 import qualified Foreign.Marshal.Array as Array
 import qualified Foreign.C.String as CString
+import qualified Foreign.C.Types as C
 import Foreign.Storable (Storable, peek, )
 import Foreign.Ptr (Ptr, FunPtr, nullPtr, castPtr, )
 import Foreign.C.String (peekCString, )
@@ -271,6 +272,13 @@
     mapM_ (liftErrno . JackFFI.port_unregister (getClient client)) ports
     deactivate client
     disposeClient client
+
+
+{-
+dummy use of C that we imported in order to expose CInt constructor
+-}
+_dummy :: C.CInt
+_dummy = undefined
 
 foreign import ccall "wrapper" mkProcess :: Process -> IO (FunPtr Process)
 
diff --git a/src/Sound/JACK/FFI.hs b/src/Sound/JACK/FFI.hs
--- a/src/Sound/JACK/FFI.hs
+++ b/src/Sound/JACK/FFI.hs
@@ -25,7 +25,7 @@
 
 import Foreign.Ptr (Ptr, FunPtr)
 import Foreign.C.String (CString)
-import Foreign.C.Error (Errno, )
+import qualified Foreign.C.Error as E
 import qualified Foreign.C.Types as C
 
 import qualified Data.EnumSet as ES
@@ -153,11 +153,11 @@
 data CallbackArg = CallbackArg
 
 
-type Process = NFrames -> Ptr CallbackArg -> IO Errno
+type Process = NFrames -> Ptr CallbackArg -> IO E.Errno
 
 foreign import ccall "static jack/jack.h jack_set_process_callback"
   set_process_callback ::
-        Ptr Client -> FunPtr Process -> Ptr CallbackArg -> IO Errno
+        Ptr Client -> FunPtr Process -> Ptr CallbackArg -> IO E.Errno
 
 foreign import ccall "static jack/jack.h jack_last_frame_time"
   last_frame_time :: Ptr Client -> IO NFrames
@@ -170,10 +170,10 @@
   get_buffer_size :: Ptr Client -> IO (C.CUInt)
 
 foreign import ccall "static jack/jack.h jack_activate"
-  activate :: Ptr Client -> IO Errno
+  activate :: Ptr Client -> IO E.Errno
 
 foreign import ccall "static jack/jack.h jack_client_close"
-  client_close :: Ptr Client -> IO Errno
+  client_close :: Ptr Client -> IO E.Errno
 
 foreign import ccall "static jack/jack.h jack_get_ports"
   get_ports :: Ptr Client -> CString -> CString -> C.CULong -> IO (Ptr CString)
@@ -181,13 +181,13 @@
 
 -- may return eEXIST
 foreign import ccall "static jack/jack.h jack_connect"
-  connect :: Ptr Client -> PortName -> PortName -> IO Errno
+  connect :: Ptr Client -> PortName -> PortName -> IO E.Errno
 
 foreign import ccall "static jack/jack.h jack_disconnect"
-  disconnect :: Ptr Client -> PortName -> PortName -> IO Errno
+  disconnect :: Ptr Client -> PortName -> PortName -> IO E.Errno
 
 foreign import ccall "static jack/jack.h jack_port_unregister"
-  port_unregister :: Ptr Client -> Ptr (Port a) -> IO Errno
+  port_unregister :: Ptr Client -> Ptr (Port a) -> IO E.Errno
 
 foreign import ccall "static jack/jack.h jack_deactivate"
-  deactivate :: Ptr Client -> IO Errno
+  deactivate :: Ptr Client -> IO E.Errno
diff --git a/src/Sound/JACK/FFI/MIDI.chs b/src/Sound/JACK/FFI/MIDI.chs
--- a/src/Sound/JACK/FFI/MIDI.chs
+++ b/src/Sound/JACK/FFI/MIDI.chs
@@ -30,9 +30,9 @@
 import Foreign.ForeignPtr (withForeignPtr, )
 import Foreign.Ptr (Ptr, castPtr, )
 import Foreign.Storable (Storable, peekByteOff, pokeByteOff, sizeOf, alignment, peek, poke)
+import qualified Foreign.C.Error as E
 import qualified Foreign.C.Types as C
 import Foreign.C.Types (CUInt, CUChar, )
-import Foreign.C.Error (Errno, )
 import Data.Word (Word8, )
 
 import qualified Data.ByteString as B
@@ -135,7 +135,7 @@
   get_event_count :: Ptr EventBuffer -> IO NFrames
 
 foreign import ccall "static jack/midiport.h jack_midi_event_get"
-  event_get :: Ptr RawEvent -> Ptr EventBuffer -> NFrames -> IO Errno
+  event_get :: Ptr RawEvent -> Ptr EventBuffer -> NFrames -> IO E.Errno
 
 foreign import ccall "static jack/midiport.h jack_midi_clear_buffer"
   clear_buffer :: Ptr EventBuffer -> IO ()
@@ -145,4 +145,4 @@
   event_reserve :: Ptr EventBuffer -> NFrames -> C.CSize -> IO (Ptr Word8)
 
 foreign import ccall "static jack/midiport.h jack_midi_event_write"
-  event_write :: Ptr EventBuffer -> NFrames -> Ptr Word8 -> C.CULong -> IO Errno
+  event_write :: Ptr EventBuffer -> NFrames -> Ptr Word8 -> C.CULong -> IO E.Errno
