diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,11 @@
 Changes
 =======
 
+Version 0.2.4.1
+---------------
+
+Fix a bug with empty CPP defines (such as `-DFOO`)
+
 Version 0.2.4
 -------------
 
diff --git a/haskell-packages.cabal b/haskell-packages.cabal
--- a/haskell-packages.cabal
+++ b/haskell-packages.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                haskell-packages
-version:             0.2.4
+version:             0.2.4.1
 synopsis:            Haskell suite library for package management and integration with Cabal
 description:         See <http://documentup.com/haskell-suite/haskell-packages>
 license:             MIT
diff --git a/src/Distribution/HaskellSuite/Cabal.hs b/src/Distribution/HaskellSuite/Cabal.hs
--- a/src/Distribution/HaskellSuite/Cabal.hs
+++ b/src/Distribution/HaskellSuite/Cabal.hs
@@ -220,7 +220,7 @@
           def :: (String, String)
           def =
             case span (/= '=') str of
-              (_, []) -> (str, "")
+              (_, []) -> (str, "1")
               (sym, _:var) -> (sym, var)
           in Endo $ \opts -> opts { defines = def : defines opts }