Move required language extensions into pragmas for shootout.

Summary: That way they are easier to compile with plain calls to ghc.

Test Plan: make clean && make boot && make

Reviewers: O26 nofib, bgamari

Reviewed By: bgamari

Subscribers: bgamari

Differential Revision: https://phabricator.haskell.org/D5437

shootout/binary-trees/Main.hs

+{-# LANGUAGE BangPatterns #-}
 --
 -- The Computer Language Benchmarks Game
 -- http://benchmarksgame.alioth.debian.org/
@@ -53,7 +54,7 @@ depth d m
   where n = bit (m - d + minN)
 
 -- allocate and check lots of trees
-sumT :: Int -> Int -> Int -> Int	
+sumT :: Int -> Int -> Int -> Int
 sumT d 0 t = t
 sumT  d i t = a `par` b `par` sumT d (i-1) ans
   where a = check (make i    d)