warnings :: [String] -> [String]
warnings = map format . filter (isPrefixOf "-optghc")
  where
    format arg = concat ["Warning: `", arg, "' means `-o ", drop 2 arg, "', did you mean `-", arg, "'?"]
warnings :: [String] -> [String]
warnings = map format . filter (isPrefixOf "-optghc")
  where
    format arg = concat ["Warning: `", arg, "' means `-o ", drop 2 arg, "', did you mean `-", arg, "'?"]
warnings = map format . filter (isPrefixOf "-optghc")
  where
    format arg = concat ["Warning: `", arg, "' means `-o ", drop 2 arg, "', did you mean `-", arg, "'?"]