Treat "cabal --flag command" as "cabal command --flag"

eg "cabal -v configure" to mean "cabal configure -v"
For flags that are not recognised as global flags,
pass them on to the sub-command.

Distribution/GetOpt.hs

@@ -233,7 +233,7 @@ shortOpt y ys rs optDescr = short ads ys rs
         short (OptArg f _:_) [] rest     = (Opt (f Nothing),rest)
         short (OptArg f _:_) xs rest     = (Opt (f (Just xs)),rest)
         short []             [] rest     = (UnreqOpt optStr,rest)
-        short []             xs rest     = (UnreqOpt optStr,('-':xs):rest)
+        short []             xs rest     = (UnreqOpt (optStr++xs),rest)
 
 -- miscellaneous error formatting
 

Distribution/Simple/Command.hs

@@ -406,24 +406,33 @@ addCommonFlags showOrParseArgs options =
 
 commandParseArgs :: CommandUI flags -> Bool -> [String]
                  -> CommandParse (flags -> flags, [String])
-commandParseArgs command ordered args =
+commandParseArgs command global args =
   let options = addCommonFlags ParseArgs
               $ commandGetOpts ParseArgs command
-      order | ordered   = GetOpt.RequireOrder
+      order | global    = GetOpt.RequireOrder
             | otherwise = GetOpt.Permute
-  in case GetOpt.getOpt order options args of
-    (flags, _,    _)
-      | not (null [ () | Left ListOptionsFlag <- flags ])
-                      -> CommandList (commandListOptions command)
-      | not (null [ () | Left HelpFlag <- flags ])
-                      -> CommandHelp (commandHelp command)
-    (flags, opts, []) -> CommandReadyToGo (accumFlags flags , opts)
-    (_,     _,  errs) -> CommandErrors errs
+  in case GetOpt.getOpt' order options args of
+    (flags, _, _,  _)
+      | any listFlag flags -> CommandList (commandListOptions command)
+      | any helpFlag flags -> CommandHelp (commandHelp command)
+      where listFlag (Left ListOptionsFlag) = True; listFlag _ = False
+            helpFlag (Left HelpFlag)        = True; helpFlag _ = False
+    (flags, opts, opts', [])
+      | global || null opts' -> CommandReadyToGo (accum flags, mix opts opts')
+      | otherwise            -> CommandErrors (unrecognised opts')
+    (_, _, _, errs)          -> CommandErrors errs
 
   where -- Note: It is crucial to use reverse function composition here or to
         -- reverse the flags here as we want to process the flags left to right
         -- but data flow in function compsition is right to left.
-        accumFlags flags = foldr (flip (.)) id [ f | Right f <- flags ]
+        accum flags = foldr (flip (.)) id [ f | Right f <- flags ]
+        unrecognised opts = [ "unrecognized option `" ++ opt ++ "'\n"
+                            | opt <- opts ]
+        -- For unrecognised global flags we put them in the position just after
+        -- the command, if there is one. This gives us a chance to parse them
+        -- as sub-command rather than global flags.
+        mix []     ys = ys
+        mix (x:xs) ys = x:ys++xs
 
 data CommandParse flags = CommandHelp (String -> String)
                         | CommandList [String]