fix build on windows

Utility/LockPool/Windows.hs

@@ -22,7 +22,7 @@ import Utility.LockPool.STM (LockFile, LockMode(..))
 {- Tries to lock a file with a shared lock, which allows other processes to
  - also lock it shared. Fails if the file is exclusively locked. -}
 lockShared :: LockFile -> IO (Maybe LockHandle)
-lockShared file = tryMakeLockHandle P.lockPool file
+lockShared file = fmap fst <$> tryMakeLockHandle P.lockPool file
 	(\p f -> P.tryTakeLock p f LockShared)
 	(\f _ -> fmap mk <$> F.lockShared f)
 
@@ -33,7 +33,7 @@ lockShared file = tryMakeLockHandle P.lockPool file
  - read or write by any other process. So for advisory locking of a file's
  - content, a separate LockFile should be used. -}
 lockExclusive :: LockFile -> IO (Maybe LockHandle)
-lockExclusive file = tryMakeLockHandle P.lockPool file
+lockExclusive file = fmap fst <$> tryMakeLockHandle P.lockPool file
 	(\p f -> P.tryTakeLock p f LockExclusive)
 	(\f _ -> fmap mk <$> F.lockExclusive f)
 
@@ -42,7 +42,7 @@ lockExclusive file = tryMakeLockHandle P.lockPool file
 waitToLock :: IO (Maybe lockhandle) -> IO lockhandle
 waitToLock = F.waitToLock
 
-mk :: F.LockHandle -> FileLockOps
-mk h = FileLockOps
+mk :: F.LockHandle -> (FileLockOps, ())
+mk h = (FileLockOps
 	{ fDropLock = F.dropLock h
-	}
+	}, ())

doc/bugs/Build_failing_on_Windows_since_ef3ab0769.mdwn

@@ -72,3 +72,5 @@ Utility\LockPool\Windows.hs:38:18: error:
 
 [[!meta author=jwodder]]
 [[!tag projects/datalad]]
+
+> [[fixed|done]] --[[Joey]]