--- extra-1.5.3/extra.cabal~	2017-06-13 06:58:38.000000000 +0900
+++ extra-1.5.3/extra.cabal	2018-01-09 20:24:52.221337034 +0900
@@ -74,7 +74,7 @@
     if !os(windows)
         build-depends: unix
     hs-source-dirs: test
-    ghc-options: -main-is Test -threaded "-with-rtsopts=-N4 -K1K"
+    ghc-options: -main-is Test -threaded "-with-rtsopts=-K1K"
     main-is:        Test.hs
     other-modules:
         TestCustom