More unused import warnings

Summary:

Test Plan:

src/Development/Shake/Util.hs

@@ -1,3 +1,4 @@
+{-# OPTIONS_GHC -Wno-unused-imports #-} -- Required since foldl' moves to the prelude
 
 -- | A module for useful utility functions for Shake build systems.
 module Development.Shake.Util(
@@ -10,13 +11,13 @@ import Development.Shake.Internal.Rules.File
 import qualified Data.ByteString.Char8 as BS
 import qualified General.Makefile as BS
 import Data.Tuple.Extra
-import Data.List
+import Data.List (foldl')
 import General.GetOpt
 import Data.IORef
 import Data.Maybe
 import Control.Monad.Extra
 import System.IO.Extra as IO
-
+ 
 
 -- | Given the text of a Makefile, extract the list of targets and dependencies. Assumes a
 --   small subset of Makefile syntax, mostly that generated by @gcc -MM@.