diff --git a/app/ghcup/GHCup/OptParse/Run.hs b/app/ghcup/GHCup/OptParse/Run.hs
index 1b5b05d..8321fac 100644
--- a/app/ghcup/GHCup/OptParse/Run.hs
+++ b/app/ghcup/GHCup/OptParse/Run.hs
@@ -205,9 +205,11 @@ run RunOptions{..} runAppState runLogger = runRUN runAppState (do
      [] -> liftIO $ putStr tmp
      (cmd:args) -> do
        newEnv <- liftIO $ addToPath tmp
-       if isWindows
-       then liftE $ lEM @_ @'[ProcessError] $ exec cmd args Nothing (Just newEnv)
-       else liftIO $ SPP.executeFile cmd True args (Just newEnv)
+#ifndef IS_WINDOWS
+       liftIO $ SPP.executeFile cmd True args (Just newEnv)
+#else
+       liftE $ lEM @_ @'[ProcessError] $ exec cmd args Nothing (Just newEnv)
+#endif
    pure ()
    ) >>= \case
             VRight _ -> do
diff --git a/ghcup.cabal b/ghcup.cabal
index 46cb67d..fb75a02 100644
--- a/ghcup.cabal
+++ b/ghcup.cabal
@@ -267,6 +267,9 @@ executable ghcup
 
   if os(windows)
     cpp-options: -DIS_WINDOWS
+  else
+    build-depends:
+      , unix             ^>=2.7
 
   if flag(no-exe)
     buildable: False