Merge pull request #1315 from richardkchapman/roxiemem-refactor

Fix compile error from gcc

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>

roxie/roxiemem/roxiemem.cpp

@@ -1014,6 +1014,8 @@ public:
 
 //================================================================================
 //
+class CChunkingRowManager;
+
 class CRoxieFixedRowHeap : implements IFixedRowHeap, public CInterface
 {
 public: