bring back OsPath changes

I hope that the windows test suite failure on appveyor was fixed by
updating to a newer windows there. I have not been able to reproduce
that failure in a windows 11 VM run locally.

Git/HashObject.hs

@@ -5,7 +5,7 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
-{-# LANGUAGE CPP #-}
+{-# LANGUAGE OverloadedStrings #-}
 
 module Git.HashObject where
 
@@ -82,10 +82,10 @@ instance HashableBlob Builder where
 {- Injects a blob into git. Unfortunately, the current git-hash-object
  - interface does not allow batch hashing without using temp files. -}
 hashBlob :: HashableBlob b => HashObjectHandle -> b -> IO Sha
-hashBlob h b = withTmpFile "hash" $ \tmp tmph -> do
+hashBlob h b = withTmpFile (toOsPath "hash") $ \tmp tmph -> do
 	hashableBlobToHandle tmph b
 	hClose tmph
-	hashFile h (toRawFilePath tmp)
+	hashFile h (fromOsPath tmp)
 
 {- Injects some content into git, returning its Sha.
  -