Pass io-manager=native to tests

cabal-testsuite/PackageTests/Backpack/Includes2/cabal-internal.test.hs

@@ -2,7 +2,7 @@ import Test.Cabal.Prelude
 
 main = cabalTest $ do
     skipUnlessGhcVersion ">= 8.1"
-    expectBrokenIfWindowsCI 10191 $ withProjectFile "cabal.internal.project" $ do
+    withProjectFile "cabal.internal.project" $ do
         cabal "v2-build" ["exe"]
         withPlan $ do
             r <- runPlanExe' "I" "exe" []

cabal-testsuite/PackageTests/Backpack/Includes3/cabal-external.test.hs

@@ -2,8 +2,6 @@ import Test.Cabal.Prelude
 
 main = cabalTest $ do
     skipUnlessGhcVersion ">= 8.1"
-    ghcVer <- isGhcVersion ">= 9.10"
-    skipIf "Windows + 9.10.1 (#10191)" (isWindows && ghcVer)
     withProjectFile "cabal.external.project" $ do
         cabal "v2-build" ["exe"]
         withPlan $ do

cabal-testsuite/PackageTests/Backpack/Includes3/cabal-internal.test.hs

@@ -2,7 +2,7 @@ import Test.Cabal.Prelude
 
 main = cabalTest $ do
     skipUnlessGhcVersion ">= 8.1"
-    expectBrokenIfWindowsCI 10191 $ withProjectFile "cabal.internal.project" $ do
+    withProjectFile "cabal.internal.project" $ do
         cabal "v2-build" ["exe"]
         withPlan $ do
             r <- runPlanExe' "I" "exe" []

cabal-testsuite/PackageTests/Backpack/T6385/cabal.test.hs

@@ -1,6 +1,6 @@
 import Test.Cabal.Prelude
 main =
-  cabalTest $ expectBrokenIfWindows 10191 $ withShorterPathForNewBuildStore $ do
+  cabalTest $ withShorterPathForNewBuildStore $ do
     skipUnlessGhcVersion ">= 8.1"
     withRepo "repo" $ do
       cabal "v2-build" ["T6385"]

cabal-testsuite/src/Test/Cabal/Prelude.hs

@@ -356,9 +356,15 @@ cabalGArgs global_args cmd args input = do
             [ "--store-dir=" ++ storeDir | Just storeDir <- [testMaybeStoreDir env] ]
             ++ global_args
 
+        rts_args =
+            if buildOS == Windows
+            then ["+RTS", "--io-manager=native", "-RTS"]
+            else []
+
         cabal_args = global_args'
                   ++ [ cmd, marked_verbose ]
                   ++ extra_args
+                  ++ rts_args
                   ++ args
     defaultRecordMode RecordMarked $ do
     recordHeader ["cabal", cmd]

cabal-testsuite/src/Test/Cabal/Server.hs

@@ -29,6 +29,7 @@ import System.Exit
 import Data.List (intercalate, isPrefixOf)
 import Distribution.Simple.Program.Db
 import Distribution.Simple.Program
+import Distribution.System
 import Control.Exception
 import qualified Control.Exception as E
 import Control.Monad
@@ -221,7 +222,11 @@ runMain ref m = do
 startServer :: Chan ServerLogMsg -> ScriptEnv -> IO Server
 startServer chan senv = do
     (prog, _) <- requireProgram verbosity ghcProgram (runnerProgramDb senv)
-    let ghc_args = runnerGhcArgs senv Nothing ++ ["--interactive", "-v0", "-ignore-dot-ghci"]
+    let rts_args =
+          if buildOS == Windows
+          then ["+RTS", "--io-manager=native", "-RTS"]
+          else []
+        ghc_args = runnerGhcArgs senv Nothing ++ ["--interactive", "-v0", "-ignore-dot-ghci"] ++ rts_args
         proc_spec = (proc (programPath prog) ghc_args) {
                         create_group = True,
                         -- Closing fds is VERY important to avoid