diff --git a/src/runtime/haskell/Data/Binary/Builder.hs b/src/runtime/haskell/Data/Binary/Builder.hs
index cccbe6fa4..20e287237 100644
--- a/src/runtime/haskell/Data/Binary/Builder.hs
+++ b/src/runtime/haskell/Data/Binary/Builder.hs
@@ -1,5 +1,4 @@
-{-# LANGUAGE CPP #-}
-{-# OPTIONS_GHC -fglasgow-exts #-}
+{-# LANGUAGE CPP, MagicHash #-}
 -- for unboxed shifts
 
 -----------------------------------------------------------------------------