First attempt at fixing incompabilities with newer cabal

src/tools/c/GFCC/ErrM.hs

@@ -4,6 +4,10 @@
 -- This file comes with NO WARRANTY and may be used FOR ANY PURPOSE.
 module GFCC.ErrM where
 
+-- Control.Monad.Fail import will become redundant in GHC 8.8+
+import qualified Control.Monad.Fail as Fail
+
+
 -- the Error monad: like Maybe type with error msgs
 
 data Err a = Ok a | Bad String
@@ -11,6 +15,13 @@ data Err a = Ok a | Bad String
 
 instance Monad Err where
   return      = Ok
-  fail        = Bad
   Ok a  >>= f = f a
   Bad s >>= f = Bad s
+
+#if !(MIN_VERSION_base(4,13,0))
+  fail        = Bad
+#endif
+
+instance Fail.MonadFail Err where
+  fail        = Bad
+