allow special chars to be used in proxy-auth for Cabal

gistfile1.txt

$ diff -u ./Distribution/Client/HttpUtils.hs.orig ./Distribution/Client/HttpUtils.hs
--- ./Distribution/Client/HttpUtils.hs.orig     2011-09-26 15:59:04.368889933 +0900
+++ ./Distribution/Client/HttpUtils.hs  2011-09-26 16:31:17.142379016 +0900
@@ -12,6 +12,7 @@
 import Network.HTTP
          ( Request (..), Response (..), RequestMethod (..)
          , Header(..), HeaderName(..) )
+import qualified Network.HTTP.Base
 import Network.URI
          ( URI (..), URIAuth (..), parseAbsoluteURI )
 import Network.Stream
@@ -129,6 +130,7 @@
                              '@':s' -> reverse s'
                              _      -> s
            }
+
 uri2proxy :: URI -> Maybe Proxy
 uri2proxy uri@URI{ uriScheme = "http:"
                  , uriAuthority = Just (URIAuth auth' host port)
@@ -137,9 +139,10 @@
                  then Nothing
                  else Just (AuthBasic "" usr pwd uri)
         (usr,pwd') = break (==':') auth'
-        pwd        = case pwd' of
+        pwd''      = case pwd' of
                        ':':cs -> cs
                        _      -> pwd'
+        pwd        = Network.HTTP.Base.urlDecode pwd''
 uri2proxy _ = Nothing

 mkRequest :: URI -> Request ByteString