Age code to allow reclaiming old unexecuted functions

src/mark-compact.h

Index: src/mark-compact.h
diff --git a/src/mark-compact.h b/src/mark-compact.h
index 0f19d2c86298d414aa157d67eeaa97789a49b8ba..1c72dab0c25efe69f2ec7b39940c5fa3af87cee3 100644
--- a/src/mark-compact.h
+++ b/src/mark-compact.h
@@ -593,6 +593,8 @@ class MarkCompactCollector {
 
   bool is_compacting() const { return compacting_; }
 
+  MarkingParity marking_parity() { return marking_parity_; }
+
  private:
   MarkCompactCollector();
   ~MarkCompactCollector();
@@ -625,6 +627,8 @@ class MarkCompactCollector {
 
   bool abort_incremental_marking_;
 
+  MarkingParity marking_parity_;
+
   // True if we are collecting slots to perform evacuation from evacuation
   // candidates.
   bool compacting_;