Fix build for GHC < 7.10

paf31 · paf31 · commit bd2e5839ee15 · 2015-10-26T13:51:17.000-07:00
diff --git a/src/Control/Monad/Logger.hs b/src/Control/Monad/Logger.hs
@@ -22,6 +22,7 @@ module Control.Monad.Logger where
 import Data.IORef
 
 #if __GLASGOW_HASKELL__ < 710
+import Data.Monoid
 import Control.Applicative
 #endif
 import Control.Monad (ap)
