free heap pages from mrb_close()

src/gc.c

@@ -284,6 +284,19 @@ mrb_init_heap(mrb_state *mrb)
 #endif
 }
 
+void
+mrb_free_heap(mrb_state *mrb)
+{
+  struct heap_page *page = mrb->heaps;
+  struct heap_page *tmp;
+
+  while (page) {
+    tmp = page;
+    page = page->next;
+    mrb_free(mrb, tmp);
+  }
+}
+
 static void
 gc_protect(mrb_state *mrb, struct RBasic *p)
 {

src/state.c

@@ -51,6 +51,7 @@ mrb_open()
 }
 
 void mrb_free_symtbl(mrb_state *mrb);
+void mrb_free_heap(mrb_state *mrb);
 
 void
 mrb_close(mrb_state *mrb)
@@ -72,6 +73,7 @@ mrb_close(mrb_state *mrb)
   }
   mrb_free(mrb, mrb->irep);
   mrb_free_symtbl(mrb);
+  mrb_free_heap(mrb);
   mrb_free(mrb, mrb);
 }