Disable terminal GUI on Windows (#330)

cardano-launcher/app/Main.hs

@@ -6,8 +6,10 @@ module Main where
 import           Cardano.Prelude
 import qualified Prelude
 
+import           Distribution.System (OS (Windows), buildOS)
 import           System.Environment (setEnv)
 import           System.Exit (exitWith)
+import           System.IO.Silently (hSilence)
 
 import           Formatting (bprint, build, formatToString)
 import           Formatting.Buildable (Buildable (..))
@@ -39,7 +41,7 @@ import           Data.Text.Lazy.Builder (fromString, fromText)
 
 -- | Main function.
 main :: IO ()
-main = do
+main = silence $ do
 
     logConfig       <- defaultConfigStdout
 
@@ -161,3 +163,7 @@ instance Show LauncherExceptions where
 
 instance Exception LauncherExceptions
 
+silence :: IO a -> IO a
+silence action = case buildOS of
+    Windows -> hSilence [stdout, stderr] action
+    _       -> action

cardano-launcher/cardano-launcher.cabal

@@ -82,6 +82,11 @@ executable cardano-launcher
     -- exception handling
     , safe-exceptions
     , text
+    , silently
+    , Cabal
+
+  if os(windows)
+    ghc-options: -optl-mwindows
 
   default-language:    Haskell2010
   default-extensions:  NoImplicitPrelude

stack.yaml

@@ -8,6 +8,7 @@ extra-deps:
   - quickcheck-state-machine-0.6.0  # Used a specific dependency, new release.
   - pretty-show-1.9.5               # Used for quickcheck-state-machine.
   - time-units-1.0.0
+  - silently-1.2.5.1
 
   - git: https://github.com/input-output-hk/cardano-prelude
     commit: 12ab51e27539c9cce042ded0c89efc0ccae6137a