Guard CyclicSCC with DEFINE_PATTERN_SYNONYMS (#1085)

DEFINE_PATTERN_SYNONYMS is set for GHC and MicroHs.

Author: meooow25

containers/src/Data/Graph.hs

@@ -1,19 +1,20 @@
 {-# LANGUAGE CPP #-}
+#include "containers.h"
 {-# LANGUAGE BangPatterns #-}
 #if __GLASGOW_HASKELL__
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE DeriveLift #-}
-{-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE StandaloneDeriving #-}
 {-# LANGUAGE Safe #-}
 {-# LANGUAGE TemplateHaskellQuotes #-}
+#endif
+#ifdef DEFINE_PATTERN_SYNONYMS
+{-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE ViewPatterns #-}
 #endif
 
-#include "containers.h"
-
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Data.Graph
@@ -81,7 +82,7 @@ module Data.Graph (
 
     -- * Strongly Connected Components
     , SCC(..
-#ifdef __GLASGOW_HASKELL__
+#ifdef DEFINE_PATTERN_SYNONYMS
       , CyclicSCC
 #endif
       )
@@ -167,15 +168,17 @@ data SCC vertex
            , Read -- ^ @since 0.5.9
            )
 
-#ifdef __GLASGOW_HASKELL__
+#ifdef DEFINE_PATTERN_SYNONYMS
 -- | Partial pattern synonym for backward compatibility with @containers < 0.7@.
 pattern CyclicSCC :: [vertex] -> SCC vertex
 pattern CyclicSCC xs <- NECyclicSCC (NE.toList -> xs) where
   CyclicSCC [] = error "CyclicSCC: an argument cannot be an empty list"
   CyclicSCC (x : xs) = NECyclicSCC (x :| xs)
 
 {-# COMPLETE AcyclicSCC, CyclicSCC #-}
+#endif
 
+#ifdef __GLASGOW_HASKELL__
 -- | @since 0.5.9
 deriving instance Data vertex => Data (SCC vertex)