removed all uses of undefined from code base

It's a code smell, can lead to hard to diagnose error messages.

Utility/DirWatcher.hs

@@ -57,7 +57,7 @@ eventsCoalesce = False
 #if (WITH_KQUEUE || WITH_FSEVENTS)
 eventsCoalesce = True
 #else
-eventsCoalesce = undefined
+eventsCoalesce = error "eventsCoalesce not defined"
 #endif
 #endif
 
@@ -78,7 +78,7 @@ closingTracked = True
 #if WITH_KQUEUE
 closingTracked = False
 #else
-closingTracked = undefined
+closingTracked = error "closingTracked not defined"
 #endif
 #endif
 
@@ -93,7 +93,7 @@ modifyTracked = True
 #if WITH_KQUEUE
 modifyTracked = False
 #else
-modifyTracked = undefined
+modifyTracked = error "modifyTracked not defined"
 #endif
 #endif
 
@@ -131,7 +131,7 @@ watchDir dir prune scanevents hooks runstartup =
 #else
 type DirWatcherHandle = ()
 watchDir :: FilePath -> Pruner -> Bool -> WatchHooks -> (IO () -> IO ()) -> IO DirWatcherHandle
-watchDir = undefined
+watchDir = error "watchDir not defined"
 #endif
 #endif
 #endif
@@ -150,7 +150,7 @@ stopWatchDir = FSEvents.eventStreamDestroy
 #if WITH_WIN32NOTIFY
 stopWatchDir = Win32Notify.killWatchManager
 #else
-stopWatchDir = undefined
+stopWatchDir = error "stopWatchDir not defined"
 #endif
 #endif
 #endif

Utility/Directory.hs

@@ -111,7 +111,7 @@ moveFile src dest = tryIO (rename src dest) >>= onrename
 			-- But, mv will move into a directory if
 			-- dest is one, which is not desired.
 			whenM (isdir dest) rethrow
-			viaTmp mv dest undefined
+			viaTmp mv dest ""
 	  where
 		rethrow = throwM e
 		mv tmp _ = do

Utility/FileMode.hs

@@ -124,7 +124,7 @@ withUmask _ a = a
 #endif
 
 combineModes :: [FileMode] -> FileMode
-combineModes [] = undefined
+combineModes [] = 0
 combineModes [m] = m
 combineModes (m:ms) = foldl unionFileModes m ms
 

Utility/Metered.hs

@@ -144,7 +144,7 @@ defaultChunkSize :: Int
 defaultChunkSize = 32 * k - chunkOverhead
   where
 	k = 1024
-	chunkOverhead = 2 * sizeOf (undefined :: Int) -- GHC specific
+	chunkOverhead = 2 * sizeOf (1 :: Int) -- GHC specific
 
 data OutputHandler = OutputHandler
 	{ quietMode :: Bool

Utility/Touch.hsc

@@ -54,8 +54,8 @@ instance Storable TimeSpec where
 	-- use the larger alignment of the two types in the struct
 	alignment _ = max sec_alignment nsec_alignment
 	  where
-		sec_alignment = alignment (undefined::CTime)
-		nsec_alignment = alignment (undefined::CLong)
+		sec_alignment = alignment (1::CTime)
+		nsec_alignment = alignment (1::CLong)
 	sizeOf _ = #{size struct timespec}
 	peek ptr = do
 		sec <- #{peek struct timespec, tv_sec} ptr
@@ -92,7 +92,7 @@ touchBoth file atime mtime follow =
  -}
 
 instance Storable TimeSpec where
-	alignment _ = alignment (undefined::CLong)
+	alignment _ = alignment (1::CLong)
 	sizeOf _ = #{size struct timeval}
 	peek ptr = do
 		sec <- #{peek struct timeval, tv_sec} ptr