use openTempFile from file-io

And follow-on changes.

Note that relatedTemplate was changed to operate on a RawFilePath, and
so when it counts the length, it is now the number of bytes, not the
number of code points. This will just make it truncate shorter strings
in some cases, the truncation is still unicode aware.

When not building with the OsPath flag, toOsPath . fromRawFilePath and
fromRawFilePath . fromOsPath do extra conversions back and forth between
String and ByteString. That overhead could be avoided, but that's the
non-optimised build mode, so didn't bother.

Sponsored-by: unqueued

Assistant/DaemonStatus.hs

@@ -22,6 +22,7 @@ import qualified Remote
 import qualified Types.Remote as Remote
 import Config.DynamicConfig
 import Annex.SpecialRemote.Config
+import qualified Utility.FileIO as F
 
 import Control.Concurrent.STM
 import System.Posix.Types
@@ -121,9 +122,9 @@ startDaemonStatus = do
  - and parts of it are not relevant. -}
 writeDaemonStatusFile :: FilePath -> DaemonStatus -> IO ()
 writeDaemonStatusFile file status = 
-	viaTmp writeFile file =<< serialized <$> getPOSIXTime
+	viaTmp F.writeFile' (toOsPath (toRawFilePath file)) =<< serialized <$> getPOSIXTime
   where
-	serialized now = unlines
+	serialized now = encodeBS $ unlines
 		[ "lastRunning:" ++ show now
 		, "scanComplete:" ++ show (scanComplete status)
 		, "sanityCheckRunning:" ++ show (sanityCheckRunning status)