fix touch and statfs to work on any files in any locale

Use withCAString rather than withCString.

XXX Actually, this only works in non-unicode locales when presented with
unicode characters. Help?

Command/Add.hs

@@ -84,9 +84,9 @@ cleanup file key hascontent = do
 			-- file it points to
 			-- XXX Currently broken on non-utf8 locales when
 			-- dealing with utf-8 filenames.
-			--liftIO $ do
-				--mtime <- modificationTime <$> getFileStatus file
-				--touch file (TimeSpec mtime) False
+			liftIO $ do
+				mtime <- modificationTime <$> getFileStatus file
+				touch file (TimeSpec mtime) False
 
 	force <- Annex.getState Annex.force
 	if force

Utility/StatFS.hsc

@@ -50,8 +50,6 @@ module Utility.StatFS ( FileSystemStats(..), getFileSystemStats ) where
 import Foreign
 import Foreign.C.Types
 import Foreign.C.String
-import Data.ByteString (useAsCString)
-import Data.ByteString.Char8 (pack)
 
 #if defined (__FreeBSD__) || defined (__FreeBSD_kernel__) || defined (__APPLE__)
 # include <sys/param.h>
@@ -105,7 +103,7 @@ getFileSystemStats path =
   return Nothing
 #else
   allocaBytes (#size struct statfs) $ \vfs ->
-  useAsCString (pack path) $ \cpath -> do
+  withCAString path $ \cpath -> do
     res <- c_statfs cpath vfs
     if res == -1 then return Nothing
       else do

Utility/Touch.hsc

@@ -64,7 +64,7 @@ foreign import ccall "utimensat"
 
 touchBoth file atime mtime follow = 
 	allocaArray 2 $ \ptr ->
-	withCString file $ \f -> do
+	withCAString file $ \f -> do
 		pokeArray ptr [atime, mtime]
 		r <- c_utimensat at_fdcwd f ptr flags
 		when (r /= 0) $ throwErrno "touchBoth"
@@ -101,7 +101,7 @@ foreign import ccall "lutimes"
 
 touchBoth file atime mtime follow = 
 	allocaArray 2 $ \ptr ->
-	withCString file $ \f -> do
+	withCAString file $ \f -> do
 		pokeArray ptr [atime, mtime]
 		r <- syscall f ptr
 		if (r /= 0)