Switch when using cabal-dev case. Bugfix of cabal-dev case.

GHCMod.hs

@@ -2,6 +2,7 @@
 
 module Main where
 
+import CabalDev (modifyOptions)
 import Browse
 import Check
 import Control.Applicative
@@ -89,8 +90,8 @@ instance Exception GHCModError
 main :: IO ()
 main = flip catches handlers $ do
     args <- getArgs
-    let (opt,cmdArg) = parseArgs argspec args
-    res <- case safelist cmdArg 0 of
+    let (opt',cmdArg) = parseArgs argspec args
+    res <- modifyOptions opt' >>= \opt -> case safelist cmdArg 0 of
       "browse" -> concat <$> mapM (browseModule opt) (tail cmdArg)
       "list"   -> listModules opt
       "check"  -> withFile (checkSyntax opt) (safelist cmdArg 1)