Eliminate warnings about deprecated use of catch and try

This is also needed for compatibility with GHC 7.6.

src/compiler/GF/System/Catch.hs

@@ -0,0 +1,14 @@
+-- | Isolate backwards incompatible library changes to 'catch' and 'try'
+{-# LANGUAGE CPP #-}
+module GF.System.Catch where
+import qualified System.IO.Error as S
+
+#include "cabal_macros.h"
+
+#if MIN_VERSION_base(4,4,0)
+catch = S.catchIOError
+try = S.tryIOError
+#else
+catch = S.catch
+try = S.try
+#endif