diff --git a/ghc-datasize.cabal b/ghc-datasize.cabal
--- a/ghc-datasize.cabal
+++ b/ghc-datasize.cabal
@@ -1,5 +1,5 @@
 name:               ghc-datasize
-version:            0.1.1
+version:            0.1.2
 license:            BSD3
 license-file:       LICENSE
 category:           GHC, Debug, Development
@@ -15,7 +15,7 @@
                     recursive data structures is supported. All sizes are in
                     Bytes.
 
-tested-with: GHC == 7.4.2, GHC == 7.6.1
+tested-with: GHC == 7.4.2, GHC == 7.6.1, GHC == 7.8.3
 
 Library
   Exposed-modules: GHC.DataSize
diff --git a/src/GHC/DataSize.hs b/src/GHC/DataSize.hs
--- a/src/GHC/DataSize.hs
+++ b/src/GHC/DataSize.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 {- |
    Module      : GHC.DataSize
    Copyright   : (c) Dennis Felsing
@@ -13,11 +14,14 @@
 
 import GHC.HeapView hiding (size)
 
-import GHC.Constants (wORD_SIZE)
-
 import Control.Monad
 
 import System.Mem
+
+-- This used to be available via GHC.Constants
+#include "MachDeps.h"
+wORD_SIZE :: Int
+wORD_SIZE = SIZEOF_HSWORD
 
 --import qualified Data.IntMap as IntMap