Fix warnings in 16 modules, mostly forward compatibility warnings from GHC 7.8

src/compiler/GF/Compile/GeneratePMCFG.hs

@@ -36,6 +36,7 @@ import Data.Array.IArray
 import Data.Array.Unboxed
 --import Data.Maybe
 --import Data.Char (isDigit)
+import Control.Applicative(Applicative(..))
 import Control.Monad
 import Control.Monad.Identity
 --import Control.Exception
@@ -247,6 +248,10 @@ newtype CnvMonad a = CM {unCM :: SourceGrammar
                               -> ([ProtoFCat],[Symbol])
                               -> Branch b}
 
+instance Applicative CnvMonad where
+  pure = return
+  (<*>) = ap
+
 instance Monad CnvMonad where
     return a   = CM (\gr c s -> c a s)
     CM m >>= k = CM (\gr c s -> m gr (\a s -> unCM (k a) gr c s) s)

src/compiler/GF/Compile/GetGrammar.hs

@@ -30,7 +30,7 @@ import GF.Compile.ReadFiles(parseSource,lift)
 import qualified Data.ByteString.Char8 as BS
 import Data.Char(isAscii)
 import Control.Monad (foldM,when,unless)
-import System.Cmd (system)
+import System.Process (system)
 import System.Directory(removeFile,getCurrentDirectory)
 import System.FilePath(makeRelative)
 

src/compiler/GF/Compile/TypeCheck/ConcreteNew.hs

@@ -9,6 +9,8 @@ import GF.Compile.TypeCheck.Primitives
 import GF.Infra.CheckM
 --import GF.Infra.UseIO
 import GF.Data.Operations
+import Control.Applicative(Applicative(..))
+import Control.Monad(ap)
 
 import GF.Text.Pretty
 import Data.List (nub, (\\), tails)
@@ -467,6 +469,10 @@ instance Monad TcM where
                                 TcFail    msgs -> TcFail msgs)
   fail     = tcError . pp
 
+instance Applicative TcM where
+  pure = return
+  (<*>) = ap
+
 instance Functor TcM where
   fmap f g = TcM (\ms msgs -> case unTcM g ms msgs of
                            TcOk x ms msgs -> TcOk (f x) ms msgs