Add deprecation warning in Control.Monad.Class.MonadMVar.

Author: jorisdral

io-classes/io-classes.cabal

@@ -58,6 +58,7 @@ library
                        Control.Monad.Class.MonadAsync
                        Control.Monad.Class.MonadEventlog
                        Control.Monad.Class.MonadFork
+                       Control.Monad.Class.MonadMVar
                        Control.Monad.Class.MonadSay
                        Control.Monad.Class.MonadST
                        Control.Monad.Class.MonadSTM

io-classes/src/Control/Monad/Class/MonadMVar.hs

@@ -0,0 +1,3 @@
+module Control.Monad.Class.MonadMVar {-# DEPRECATED "Use Control.Concurrent.Class.MonadMVar" #-} (module X) where
+
+import Control.Concurrent.Class.MonadMVar as X