diff --git a/hgeos.cabal b/hgeos.cabal
--- a/hgeos.cabal
+++ b/hgeos.cabal
@@ -1,5 +1,5 @@
 name:                 hgeos
-version:              0.1.7.0
+version:              0.1.7.1
 synopsis:             Simple Haskell bindings to GEOS C API
 description:
   Simple Haskell bindings to the <https://trac.osgeo.org/geos/ GEOS>
@@ -24,7 +24,7 @@
 library
   hs-source-dirs:     src/lib
   default-language:   Haskell2010
-  build-depends:      base >= 4.7 && < 5
+  build-depends:      base >= 4.6 && < 5
                     , transformers
   extra-libraries:    geos_c
   c-sources:          src/lib/Data/Geolocation/GEOS/helpers.c
@@ -39,7 +39,7 @@
   main-is:            Main.hs
   default-language:   Haskell2010
   build-depends:      MissingH
-                    , base >= 4.7 && < 5
+                    , base >= 4.6 && < 5
                     , hgeos
                     , mtl
                     , transformers
diff --git a/src/lib/Data/Geolocation/GEOS.hs b/src/lib/Data/Geolocation/GEOS.hs
--- a/src/lib/Data/Geolocation/GEOS.hs
+++ b/src/lib/Data/Geolocation/GEOS.hs
@@ -58,6 +58,7 @@
     , writeGeometry
     ) where
 
+import Control.Applicative
 import Control.Exception
 import Control.Monad
 import Data.Geolocation.GEOS.Imports
diff --git a/src/lib/Data/Geolocation/GEOS/Imports.hs b/src/lib/Data/Geolocation/GEOS/Imports.hs
--- a/src/lib/Data/Geolocation/GEOS/Imports.hs
+++ b/src/lib/Data/Geolocation/GEOS/Imports.hs
@@ -230,13 +230,13 @@
     c_finishGEOS_r :: GEOSContextHandle -> IO ()
 
 -- |Wraps @getErrorMessage@ helper function
-foreign import ccall "helpers.h getErrorMessage"
+foreign import ccall "getErrorMessage"
     c_getErrorMessage :: IO CString
 
 -- |Wraps @getNoticeMessage@ helper function
-foreign import ccall "helpers.h getNoticeMessage"
+foreign import ccall "getNoticeMessage"
     c_getNoticeMessage :: IO CString
 
 -- |Wraps @initializeGEOSWithHandlers@ helper function
-foreign import ccall "helpers.h initializeGEOSWithHandlers"
+foreign import ccall "initializeGEOSWithHandlers"
     c_initializeGEOSWithHandlers :: IO GEOSContextHandle
diff --git a/src/lib/Data/Geolocation/GEOS/Trans.hs b/src/lib/Data/Geolocation/GEOS/Trans.hs
--- a/src/lib/Data/Geolocation/GEOS/Trans.hs
+++ b/src/lib/Data/Geolocation/GEOS/Trans.hs
@@ -47,8 +47,10 @@
     , writeGeometryM
     ) where
 
+import Control.Applicative
 import Control.Monad.Trans.Maybe
 import Data.Geolocation.GEOS
+import Data.Word
 
 unaryGEOSFunc :: (a -> IO (Maybe b)) -> a -> MaybeT IO b
 unaryGEOSFunc = (MaybeT .)
diff --git a/src/lib/Data/Geolocation/GEOS/helpers.c b/src/lib/Data/Geolocation/GEOS/helpers.c
--- a/src/lib/Data/Geolocation/GEOS/helpers.c
+++ b/src/lib/Data/Geolocation/GEOS/helpers.c
@@ -1,4 +1,3 @@
-#include "helpers.h"
 #include <geos_c.h>
 #include <stdarg.h>
 #include <stdio.h>