Eliminate warnings about deprecated use of catch and try

This is also needed for compatibility with GHC 7.6.

gf.cabal

@@ -95,7 +95,7 @@ library
     Data.Binary.IEEE754
 
 executable gf
-  build-depends: base >= 4.2,
+  build-depends: base >= 4.2 && <5,
                  array,
                  containers,
                  bytestring,
@@ -146,8 +146,9 @@ executable gf
     GF.Infra.Option
     GF.Infra.UseIO
     GF.Infra.CheckM
-    GF.System.Signal
+    GF.System.Catch
     GF.System.Console
+    GF.System.Signal
     GF.Command.Commands
     GF.Command.Interpreter
     GF.Command.Abstract

src/compiler/GF/Compile/GetGrammar.hs

@@ -14,8 +14,11 @@
 
 module GF.Compile.GetGrammar (getSourceModule) where
 
+import Prelude hiding (catch)
+
 import GF.Data.Operations
 
+import GF.System.Catch
 import GF.Infra.UseIO
 import GF.Infra.Option(Options,optPreprocessors,addOptions,flag)
 import GF.Grammar.Lexer

src/compiler/GF/Compile/ReadFiles.hs

@@ -23,6 +23,8 @@ module GF.Compile.ReadFiles
              gfoFile,gfFile,isGFO,gf2gfo,
              getOptionsFromFile) where
 
+import Prelude hiding (catch)
+import GF.System.Catch
 import GF.Infra.UseIO
 import GF.Infra.Option
 import GF.Infra.Ident

src/compiler/GF/Infra/SIO.hs

@@ -21,7 +21,7 @@ module GF.Infra.SIO(
 import Prelude hiding (putStrLn,print)
 import Control.Monad(liftM)
 import System.IO(Handle,hPutStrLn,hFlush,stdout)
-import System.IO.Error(try)
+import GF.System.Catch(try)
 import System.Cmd(system)
 import System.Environment(getEnv)
 import Control.Concurrent.Chan(newChan,writeChan,getChanContents)

src/compiler/GF/Infra/UseIO.hs

@@ -15,14 +15,17 @@
 
 module GF.Infra.UseIO where
 
+import Prelude hiding (catch)
+
 import GF.Data.Operations
 import GF.Infra.Option
+import GF.System.Catch
 import Paths_gf(getDataDir)
 
 import System.Directory
 import System.FilePath
 import System.IO
-import System.IO.Error
+import System.IO.Error(isUserError,ioeGetErrorString)
 import System.Environment
 import System.Exit
 import System.CPUTime

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

src/compiler/GFServer.hs

@@ -8,7 +8,8 @@ import Control.Monad.State(StateT(..),get,gets,put)
 import Control.Monad.Error(ErrorT(..),Error(..))
 import System.Random(randomRIO)
 import System.IO(stderr,hPutStrLn)
-import System.IO.Error(try,isAlreadyExistsError)
+import GF.System.Catch(try)
+import System.IO.Error(isAlreadyExistsError)
 import System.Directory(doesDirectoryExist,doesFileExist,createDirectory,
                         setCurrentDirectory,getCurrentDirectory,
                         getDirectoryContents,removeFile,removeDirectory)