haskellPackages.threads: add workaround for flaky test (#467518)

pkgs/development/haskell-modules/configuration-nix.nix

@@ -2129,4 +2129,7 @@ builtins.intersectAttrs super {
   cpython = doJailbreak super.cpython;
 
   botan-bindings = super.botan-bindings.override { botan = pkgs.botan3; };
+
+  # Workaround for flaky test: https://github.com/basvandijk/threads/issues/10
+  threads = appendPatch ./patches/threads-flaky-test.patch super.threads;
 }

pkgs/development/haskell-modules/patches/threads-flaky-test.patch

@@ -0,0 +1,13 @@
+diff --git a/test/test.hs b/test/test.hs
+index 0251552..dc799a7 100644
+--- a/test/test.hs
++++ b/test/test.hs
+@@ -214,7 +214,7 @@ wrap :: (ThreadGroup -> Fork a) -> (Fork a -> IO b) -> IO b
+ wrap doFork test = ThreadGroup.new >>= test . doFork
+ 
+ test_group_single_wait :: (ThreadGroup -> Fork ()) -> Assertion
+-test_group_single_wait doFork = assert $ fmap isJustTrue $ timeout (10 * a_moment) $ do
++test_group_single_wait doFork = assert $ fmap isJustTrue $ timeout (100 * a_moment) $ do
+   tg <- ThreadGroup.new
+   r <- newIORef False
+   _ <- doFork tg $ do