git style filename quoting for giveup

When the filenames are part of the git repository or other files that
might have attacker-controlled names, quote them in error messages.

This is fairly complete, although I didn't do the one in
Utility.DirWatcher.INotify.hs because that doesn't have access to
Git.Filename or Annex.

But it's also quite possible I missed some. And also while scanning for
these, I found giveup used with other things that could be attacker
controlled to contain control characters (eg Keys). So, I'm thinking
it would also be good for giveup to just filter out control characters.
This commit is then not the only line of defence, but just good
formatting when git-annex displays a filename in an error message.

Sponsored-by: Kevin Mueller on Patreon

Command/Add.hs

@@ -5,6 +5,8 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
+{-# LANGUAGE OverloadedStrings #-}
+
 module Command.Add where
 
 import Command
@@ -23,6 +25,7 @@ import Messages.Progress
 import Git.FilePath
 import Git.Types
 import Git.UpdateIndex
+import Git.Filename
 import Config.GitConfig
 import Utility.OptParse
 import Utility.InodeCache
@@ -160,7 +163,10 @@ addFile smallorlarge file s = do
 		then hashBlob =<< liftIO (R.readSymbolicLink file)
 		else if isRegularFile s
 			then hashFile file
-			else giveup $ fromRawFilePath file ++ " is not a regular file"
+			else do
+				qp <- coreQuotePath <$> Annex.getGitConfig
+				giveup $ decodeBS $ quote qp $
+					file <> " is not a regular file"
 	let treetype = if isSymbolicLink s
 		then TreeSymlink
 		else if intersectFileModes ownerExecuteMode (fileMode s) /= 0