diff --git a/testsuite/tests/concurrent/should_run/T5611.hs b/testsuite/tests/concurrent/should_run/T5611.hs
index e46859d27cad9f5777bbddb0f106e9ad60e5182f..1b056178a2647b889bd4636e6c439634a36ccc8e 100644
--- a/testsuite/tests/concurrent/should_run/T5611.hs
+++ b/testsuite/tests/concurrent/should_run/T5611.hs
@@ -4,12 +4,12 @@ import Control.Concurrent
 import Foreign.C
 import System.IO
 
-#ifdef mingw32_HOST_OS
+#if defined(mingw32_HOST_OS)
 sleep n = sleepBlock (n*1000)
-foreign import stdcall unsafe "Sleep" sleepBlock :: Int -> IO ()
+foreign import stdcall safe "Sleep" sleepBlock :: Int -> IO ()
 #else
 sleep n = sleepBlock n
-foreign import ccall unsafe "sleep" sleepBlock :: Int -> IO ()
+foreign import ccall safe "sleep" sleepBlock :: Int -> IO ()
 #endif
 
 main :: IO ()