Save horazontal space in the --help output by omitting options to short flags

So instead of "-f FLAGS --flags=FLAGS" we get just "-f --flags=FLAGS"
This makes rather better use of 80 cols and means the flag descriptsion
are not squeesed into such a narrow column.

Distribution/GetOpt.hs

@@ -122,8 +122,8 @@ fmtOpt descrWidth so lo descr =
 
 fmtShort :: ArgDescr a -> Char -> String
 fmtShort (NoArg  _   ) so = "-" ++ [so]
-fmtShort (ReqArg _ ad) so = "-" ++ [so] ++ " " ++ ad
-fmtShort (OptArg _ ad) so = "-" ++ [so] ++ "[" ++ ad ++ "]"
+fmtShort (ReqArg _  _) so = "-" ++ [so]
+fmtShort (OptArg _  _) so = "-" ++ [so]
 
 fmtLong :: ArgDescr a -> String -> String
 fmtLong (NoArg  _   ) lo = "--" ++ lo

Distribution/Simple/Command.hs

@@ -178,8 +178,11 @@ commonFlags showOrParseArgs = case showOrParseArgs of
   ShowArgs  -> [help]
   ParseArgs -> [help, list]
   where
-    help = GetOpt.Option ['h', '?'] ["help"] (GetOpt.NoArg HelpFlag)
+    help = GetOpt.Option helpShortFlags ["help"] (GetOpt.NoArg HelpFlag)
              "Show this help text"
+    helpShortFlags = case showOrParseArgs of
+      ShowArgs  -> ['h']
+      ParseArgs -> ['h', '?']
     list = GetOpt.Option [] ["list-options"] (GetOpt.NoArg ListOptionsFlag)
              "Print a list of command line flags"