diff --git a/Database/HDBC/PostgreSQL/Utils.hsc b/Database/HDBC/PostgreSQL/Utils.hsc
--- a/Database/HDBC/PostgreSQL/Utils.hsc
+++ b/Database/HDBC/PostgreSQL/Utils.hsc
@@ -83,7 +83,8 @@
                  else free x
 
 cleanUpBSNulls :: B.ByteString -> B.ByteString
-cleanUpBSNulls = B.concatMap convfunc
+cleanUpBSNulls bs | 0 `B.notElem` bs = bs
+                  | otherwise = B.concatMap convfunc bs
   where convfunc 0 = bsForNull
         convfunc x = B.singleton x
         bsForNull = BCHAR8.pack "\\000"
diff --git a/HDBC-postgresql.cabal b/HDBC-postgresql.cabal
--- a/HDBC-postgresql.cabal
+++ b/HDBC-postgresql.cabal
@@ -1,5 +1,5 @@
 Name: HDBC-postgresql
-Version: 2.3.2.1
+Version: 2.3.2.2
 License: BSD3
 Maintainer: Nicolas Wu <nicolas.wu@gmail.com>
 Author: John Goerzen
diff --git a/Setup.hs b/Setup.hs
--- a/Setup.hs
+++ b/Setup.hs
@@ -1,4 +1,5 @@
 #!/usr/bin/env runhaskell
+{-# LANGUAGE MultiParamTypeClasses, FlexibleInstances #-}
 
 import Distribution.Simple
 import Distribution.PackageDescription
@@ -26,8 +27,21 @@
     } 
 }
 
+-- 'ConstOrId' is a @Cabal-1.16@ vs @Cabal-1.18@ compatibility hack,
+-- 'programFindLocation' has a new (unused in this case)
+-- parameter. 'ConstOrId' adds this parameter when types say it is
+-- mandatory.
+class ConstOrId a b where
+    constOrId :: a -> b
+
+instance ConstOrId a a where
+    constOrId = id
+
+instance ConstOrId a (b -> a) where
+    constOrId = const
+
 pgconfigProgram = (simpleProgram "pgconfig or pg_config") {
-    programFindLocation = \verbosity -> do
+    programFindLocation = \verbosity -> constOrId $ do
       pgconfig  <- findProgramLocation verbosity "pgconfig"
       pg_config <- findProgramLocation verbosity "pg_config"
       return (pgconfig `mplus` pg_config)
diff --git a/testsrc/TestTime.hs b/testsrc/TestTime.hs
--- a/testsrc/TestTime.hs
+++ b/testsrc/TestTime.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE FlexibleContexts #-}
+
 module TestTime(tests) where
 import Test.HUnit
 import Database.HDBC
@@ -14,8 +16,7 @@
 import qualified System.Time as ST
 
 instance Eq ZonedTime where
-    a == b = zonedTimeToUTC a == zonedTimeToUTC b &&
-             zonedTimeZone a == zonedTimeZone b
+    a == b = zonedTimeToUTC a == zonedTimeToUTC b
 
 testZonedTime :: ZonedTime
 testZonedTime = fromJust $ parseTime defaultTimeLocale (iso8601DateFormat (Just "%T %z"))
@@ -28,7 +29,12 @@
 
 rowdata t = [[SqlInt32 100, toSql t, SqlNull]]
 
-testDTType inputdata convToSqlValue = dbTestCase $ \dbh ->
+testDTType :: (Convertible SqlValue a, Show b, Eq b) =>
+    a
+    -> (a -> SqlValue)
+    -> (a -> b)
+    -> Test
+testDTType inputdata convToSqlValue toComparable = dbTestCase $ \dbh ->
     do run dbh ("CREATE TABLE hdbctesttime (testid INTEGER PRIMARY KEY NOT NULL, \
                 \testvalue " ++ dateTimeTypeOfSqlValue value ++ ")") []
        finally (testIt dbh) (do commit dbh
@@ -43,30 +49,32 @@
                  case r of
                    [[testidsv, testvaluesv]] -> 
                        do assertEqual "testid" (5::Int) (fromSql testidsv)
-                          assertEqual "testvalue" inputdata (fromSql testvaluesv)
+                          assertEqual "testvalue"
+                                (toComparable inputdata)
+                                (toComparable$ fromSql testvaluesv)
           value = convToSqlValue inputdata
 
-mkTest label inputdata convfunc =
-    TestLabel label (testDTType inputdata convfunc)
+mkTest label inputdata convfunc toComparable =
+    TestLabel label (testDTType inputdata convfunc toComparable)
 
 tests = TestList $
     ((TestLabel "Non-frac" $ testIt testZonedTime) :
      if supportsFracTime then [TestLabel "Frac" $ testIt testZonedTimeFrac] else [])
 
-testIt baseZonedTime = 
-    TestList [mkTest "Day" baseDay toSql,
-              mkTest "TimeOfDay" baseTimeOfDay toSql,
-              mkTest "ZonedTimeOfDay" baseZonedTimeOfDay toSql,
-              mkTest "LocalTime" baseLocalTime toSql,
-              mkTest "ZonedTime" baseZonedTime toSql,
-              mkTest "UTCTime" baseUTCTime toSql,
-              mkTest "DiffTime" baseDiffTime toSql,
-              mkTest "POSIXTime" basePOSIXTime posixToSql,
-              mkTest "ClockTime" baseClockTime toSql,
-              mkTest "CalendarTime" baseCalendarTime toSql,
-              mkTest "TimeDiff" baseTimeDiff toSql
-             ]
-    where 
+testIt baseZonedTime =
+  TestList [ mkTest "Day"            baseDay            toSql      id
+           , mkTest "TimeOfDay"      baseTimeOfDay      toSql      id
+           , mkTest "ZonedTimeOfDay" baseZonedTimeOfDay toSql      id
+           , mkTest "LocalTime"      baseLocalTime      toSql      id
+           , mkTest "ZonedTime"      baseZonedTime      toSql      id
+           , mkTest "UTCTime"        baseUTCTime        toSql      id
+           , mkTest "DiffTime"       baseDiffTime       toSql      id
+           , mkTest "POSIXTime"      basePOSIXTime      posixToSql id
+           , mkTest "ClockTime"      baseClockTime      toSql      id
+           , mkTest "CalendarTime"   baseCalendarTime   toSql      ST.toClockTime
+           , mkTest "TimeDiff"       baseTimeDiff       toSql      id
+           ]
+ where
       baseDay :: Day
       baseDay = localDay baseLocalTime