--- a/safe-exceptions.cabal
+++ b/safe-exceptions.cabal
@@ -13,6 +13,10 @@
 extra-source-files:  README.md ChangeLog.md COOKBOOK.md
 cabal-version:       >=1.10
 
+flag tests-single-threaded
+   description: Build tests single-threaded
+   default: False
+
 library
   hs-source-dirs:      src
   exposed-modules:     Control.Exception.Safe
@@ -31,7 +35,8 @@
                      , hspec
                      , safe-exceptions
                      , void
-  ghc-options:         -threaded -rtsopts -with-rtsopts=-N
+  if !flag(tests-single-threaded)
+    ghc-options:         -threaded -rtsopts -with-rtsopts=-N
   default-language:    Haskell2010
 
 source-repository head