fix mojibake reversion in display of utf8

When displaying a ByteString like "💕", safeOutput operates on
individual bytes like "\240\159\146\149" and isControl '\146' = True,
so it got truncated to just "\240".

So, only treat the low control characters, and DEL, as control
characters.

Also split Utility.Terminal out of Utility.SafeOutput. The latter needs
win32, but Utility.SafeOutput is used by Control.Exception, which is
used by Setup.

Sponsored-by: Nicholas Golder-Manning on Patreon

Annex/UntrustedFilePath.hs

@@ -10,6 +10,8 @@ module Annex.UntrustedFilePath where
 import Data.Char
 import System.FilePath
 
+import Utility.SafeOutput
+
 {- Given a string that we'd like to use as the basis for FilePath, but that
  - was provided by a third party and is not to be trusted, returns the closest
  - sane FilePath.
@@ -55,10 +57,7 @@ sanitizeLeadingFilePathCharacter s = s
 controlCharacterInFilePath :: FilePath -> Bool
 controlCharacterInFilePath = any (not . safechar)
   where
-	safechar c
-		| not (isControl c) = True
-		| c == '\t' = True
-		| otherwise = False
+	safechar c = safeOutputChar c && c /= '\n'
 
 {- ../ is a path traversal, no matter where it appears.
  -