diff --git a/Setup.hs b/Setup.hs
--- a/Setup.hs
+++ b/Setup.hs
@@ -1,2 +1,6 @@
+module Main (main) where
+
 import Distribution.Simple
-main = defaultMain
+
+main :: IO ()
+main = defaultMainWithHooks autoconfUserHooks
diff --git a/lib/Data/Time/Calendar/WeekDate.hs b/lib/Data/Time/Calendar/WeekDate.hs
--- a/lib/Data/Time/Calendar/WeekDate.hs
+++ b/lib/Data/Time/Calendar/WeekDate.hs
@@ -9,21 +9,20 @@
 -- Note that \"Week\" years are not quite the same as Gregorian years, as the first day of the year is always a Monday.
 -- The first week of a year is the first week to contain at least four days in the corresponding Gregorian year.
 toWeekDate :: Day -> (Integer,Int,Int)
-toWeekDate date@(ModifiedJulianDay mjd) = (y1,fromInteger (w1 + 1),fromInteger (mod d 7) + 1) where
+toWeekDate date@(ModifiedJulianDay mjd) = (y1,fromInteger (w1 + 1),fromInteger d_mod_7 + 1) where
+        (d_div_7, d_mod_7) = d `divMod` 7
 	(y0,yd) = toOrdinalDate date
 	d = mjd + 2
 	foo :: Integer -> Integer
 	foo y = bar (toModifiedJulianDay (fromOrdinalDate y 6))
-	bar k = (div d 7) - (div k 7)
-	w0 = bar (d - (toInteger yd) + 4)
-	(y1,w1) = if w0 == -1
-		then (y0 - 1,foo (y0 - 1))
-		else if w0 == 52
-		then if (foo (y0 + 1)) == 0
-			then (y0 + 1,0)
-			else (y0,w0)
-		else (y0,w0)
-
+	bar k = d_div_7 - k `div` 7
+	(y1,w1) = case bar (d - toInteger yd + 4) of
+	            -1 -> (y0 - 1, foo (y0 - 1))
+	            52 -> if foo (y0 + 1) == 0
+	                  then (y0 + 1, 0)
+	                  else (y0, 52)
+	            w0  -> (y0, w0)
+	
 -- | convert from ISO 8601 Week Date format. First argument is year, second week number (1-52 or 53), third day of week (1 for Monday to 7 for Sunday).
 -- Invalid week and day values will be clipped to the correct range.
 fromWeekDate :: Integer -> Int -> Int -> Day
diff --git a/lib/Data/Time/Clock/CTimeval.hs b/lib/Data/Time/Clock/CTimeval.hs
--- a/lib/Data/Time/Clock/CTimeval.hs
+++ b/lib/Data/Time/Clock/CTimeval.hs
@@ -4,7 +4,11 @@
 #ifndef mingw32_HOST_OS
 -- All Unix-specific, this
 
+#if __GLASGOW_HASKELL__ >= 709
+import Foreign
+#else
 import Foreign.Safe
+#endif
 import Foreign.C
 
 data CTimeval = MkCTimeval CLong CLong
diff --git a/lib/Data/Time/Clock/Scale.hs b/lib/Data/Time/Clock/Scale.hs
--- a/lib/Data/Time/Clock/Scale.hs
+++ b/lib/Data/Time/Clock/Scale.hs
@@ -50,7 +50,8 @@
     )
 
 -- necessary because H98 doesn't have "cunning newtype" derivation
-instance NFData DiffTime -- FIXME: Data.Fixed had no NFData instances yet at time of writing
+instance NFData DiffTime where -- FIXME: Data.Fixed had no NFData instances yet at time of writing
+        rnf dt = seq dt ()
 
 -- necessary because H98 doesn't have "cunning newtype" derivation
 instance Enum DiffTime where
diff --git a/lib/Data/Time/Clock/UTC.hs b/lib/Data/Time/Clock/UTC.hs
--- a/lib/Data/Time/Clock/UTC.hs
+++ b/lib/Data/Time/Clock/UTC.hs
@@ -70,7 +70,8 @@
     )
 
 -- necessary because H98 doesn't have "cunning newtype" derivation
-instance NFData NominalDiffTime -- FIXME: Data.Fixed had no NFData instances yet at time of writing
+instance NFData NominalDiffTime where -- FIXME: Data.Fixed had no NFData instances yet at time of writing
+        rnf ndt = seq ndt ()
 
 instance Enum NominalDiffTime where
 	succ (MkNominalDiffTime a) = MkNominalDiffTime (succ a)
diff --git a/lib/Data/Time/Format/Locale.hs b/lib/Data/Time/Format/Locale.hs
--- a/lib/Data/Time/Format/Locale.hs
+++ b/lib/Data/Time/Format/Locale.hs
@@ -14,7 +14,7 @@
 import Data.Time.LocalTime
 
 data TimeLocale = TimeLocale {
-        -- |full and abbreviated week days
+        -- |full and abbreviated week days, starting with Sunday
         wDays  :: [(String, String)],
         -- |full and abbreviated months
         months :: [(String, String)],
diff --git a/lib/Data/Time/LocalTime/TimeZone.hs b/lib/Data/Time/LocalTime/TimeZone.hs
--- a/lib/Data/Time/LocalTime/TimeZone.hs
+++ b/lib/Data/Time/LocalTime/TimeZone.hs
@@ -17,7 +17,11 @@
 import Data.Time.Clock
 import Data.Time.Clock.POSIX
 
+#if __GLASGOW_HASKELL__ >= 709
+import Foreign
+#else
 import Foreign.Safe
+#endif
 import Foreign.C
 import Control.DeepSeq
 import Data.Typeable
diff --git a/lib/cbits/HsTime.c b/lib/cbits/HsTime.c
--- a/lib/cbits/HsTime.c
+++ b/lib/cbits/HsTime.c
@@ -3,7 +3,17 @@
 
 long int get_current_timezone_seconds (time_t t,int* pdst,char const* * pname)
 {
+#if defined(_MSC_VER) || defined(__MINGW32__) || defined(_WIN32)
+    // When compiling with MinGW (which does not provide a full POSIX
+    // layer as opposed to CygWin) it's better to use the CRT's
+    // underscore-prefixed `_tzset()` variant to avoid linker issues
+    // as Microsoft considers the POSIX named `tzset()` function
+    // deprecated (see http://msdn.microsoft.com/en-us/library/ms235384.aspx)
+    _tzset();
+#else
     tzset();
+#endif
+
 #if HAVE_LOCALTIME_R
     struct tm tmd;
     struct tm* ptm = localtime_r(&t,&tmd);
diff --git a/time.cabal b/time.cabal
--- a/time.cabal
+++ b/time.cabal
@@ -1,5 +1,5 @@
 name:           time
-version:        1.5
+version:        1.5.0.1
 stability:      stable
 license:        BSD3
 license-file:   LICENSE
@@ -95,7 +95,7 @@
     type: exitcode-stdio-1.0
     build-depends:
         base,
-        time == 1.5
+        time == 1.5.0.1
     main-is: ShowDefaultTZAbbreviations.hs
 
 test-suite tests
@@ -117,7 +117,7 @@
     build-depends:
         base,
         deepseq,
-        time == 1.5,
+        time == 1.5.0.1,
         QuickCheck >= 2.5.1,
         test-framework >= 0.8,
         test-framework-quickcheck2 >= 0.3,