diff --git a/Setup.hs b/Setup.hs
--- a/Setup.hs
+++ b/Setup.hs
@@ -52,7 +52,7 @@
 buildHelper libName dirName needed url = do
 
     -- FIXME not discerning enough!
-    needsSetup <- not <$> doesDirectoryExist dirName
+    needsSetup <- not <$> doesDirectoryExist needed
 
     when needsSetup $ do
 
diff --git a/cbits/number-theory.c b/cbits/number-theory.c
--- a/cbits/number-theory.c
+++ b/cbits/number-theory.c
@@ -1,7 +1,7 @@
 /*
 **
 ** The C code is generated by [ATS/Postiats-0-3-8]
-** The starting compilation time is: 2018-1-4:  9h: 3m
+** The starting compilation time is: 2018-1-4:  9h: 8m
 **
 */
 
diff --git a/cbits/numerics.c b/cbits/numerics.c
--- a/cbits/numerics.c
+++ b/cbits/numerics.c
@@ -1,7 +1,7 @@
 /*
 **
 ** The C code is generated by [ATS/Postiats-0-3-8]
-** The starting compilation time is: 2018-1-4:  9h: 3m
+** The starting compilation time is: 2018-1-4:  9h: 8m
 **
 */
 
diff --git a/fast-arithmetic.cabal b/fast-arithmetic.cabal
--- a/fast-arithmetic.cabal
+++ b/fast-arithmetic.cabal
@@ -1,5 +1,5 @@
 name:                fast-arithmetic
-version:             0.1.0.3
+version:             0.1.0.4
 synopsis:            Fast number-theoretic functions.
 description:         Fast number-theoretic code with a high level of safety guaranteed by ATS.
 homepage:            https://github.com/vmchale/fast-arithmetic#readme