This patch adds lots of --target-X options to cabal, which are used during the
build, but which are not needed after deployment.  There may be a better way
to achieve this, so only add this if the build requires it.

--- ghc-6.10.2.orig/libraries/Cabal/Distribution/Simple/Setup.hs	2009-03-31 06:16:33.000000000 +1300
+++ ghc-6.10.2/libraries/Cabal/Distribution/Simple/Setup.hs	2009-06-18 15:54:37.000000000 +1200
@@ -106,6 +106,7 @@
 import Distribution.Simple.InstallDirs
          ( InstallDirs(..), CopyDest(..),
            PathTemplate, toPathTemplate, fromPathTemplate )
+import Distribution.Simple.ToolChain
 import Data.List (sort)
 import Data.Char (isSpace)
 import Data.Monoid (Monoid(..))
@@ -261,6 +262,7 @@
     configHcFlavor      :: Flag CompilerFlavor, -- ^The \"flavor\" of the compiler, sugh as GHC or Hugs.
     configHcPath        :: Flag FilePath, -- ^given compiler location
     configHcPkg         :: Flag FilePath, -- ^given hc-pkg location
+    configToolChain     :: ToolChain,     -- ^toolchain for cross compile
     configVanillaLib    :: Flag Bool,     -- ^Enable vanilla library
     configProfLib       :: Flag Bool,     -- ^Enable profiling in the library
     configSharedLib     :: Flag Bool,     -- ^Build shared library
@@ -320,6 +322,21 @@
       ++ programConfigurationOptions progConf showOrParseArgs
            configProgramArgs (\v fs -> fs { configProgramArgs = v })
 
+stringArg :: Monoid b => ArgPlaceHolder -> ReadE b -> (b -> [String])
+                   -> MkOptDescr (a -> b) (b -> a -> a) a
+stringArg ad mkflag showflag sf lf d get set =
+  ReqArg d (sf,lf) ad (fmap (\a b -> set a b) mkflag) (showflag . get)
+  
+toolchainOption :: String                 -- ^ option name
+                -> (ToolChain -> String)  -- ^ get function
+                -> (String -> ToolChain -> ToolChain)  -- ^ set function
+                -> OptionField ConfigFlags
+toolchainOption name get set =
+    option "" [name]
+        ("set "++name++" - default="++get defaultToolChain)
+        (get . configToolChain)
+        (\v flags -> flags { configToolChain = set v (configToolChain flags) })
+        (stringArg "OPT" (succeedReadE id) (\x -> [x]))
 
 configureOptions :: ShowOrParseArgs -> [OptionField ConfigFlags]
 configureOptions showOrParseArgs =
@@ -344,6 +361,15 @@
          "give the path to the package tool"
          configHcPkg (\v flags -> flags { configHcPkg = v })
          (reqArgFlag "PATH")
+
+      ,toolchainOption "target-gcc"        targetGCC       (\v tc -> tc {targetGCC = v})
+      ,toolchainOption "target-ld"         targetLD        (\v tc -> tc {targetLD = v})
+      ,toolchainOption "target-ar"         targetAR        (\v tc -> tc {targetAR = v})
+      ,toolchainOption "target-ranlib"     targetRANLIB    (\v tc -> tc {targetRANLIB = v})
+      ,toolchainOption "target-strip"      targetSTRIP     (\v tc -> tc {targetSTRIP = v})
+      ,toolchainOption "target-cppflags"   targetCPPFLAGS  (\v tc -> tc {targetCPPFLAGS = v})
+      ,toolchainOption "target-cflags"     targetCFLAGS    (\v tc -> tc {targetCFLAGS = v})
+      ,toolchainOption "target-ldflags"    targetLDFLAGS   (\v tc -> tc {targetLDFLAGS = v})
       ]
    ++ map liftInstallDirs installDirsOptions
    ++ [option "b" ["scratchdir"]
@@ -536,6 +562,7 @@
     configPrograms      = error "FIXME: remove configPrograms",
     configProgramPaths  = mempty,
     configProgramArgs   = mempty,
+    configToolChain     = defaultToolChain,
     configHcFlavor      = mempty,
     configHcPath        = mempty,
     configHcPkg         = mempty,
@@ -565,6 +592,7 @@
     configPrograms      = configPrograms b,
     configProgramPaths  = combine configProgramPaths,
     configProgramArgs   = combine configProgramArgs,
+    configToolChain     = configToolChain b,
     configHcFlavor      = combine configHcFlavor,
     configHcPath        = combine configHcPath,
     configHcPkg         = combine configHcPkg,