Check !RCLASS_EXT_EMBEDDED instead of SIZE_POOL_COUNT == 1

It's much more self documenting and consistent

1 files changed, 1 insertions, 1 deletions

diff --git a/internal/class.h b/internal/class.h
index bdc3bdd236..02a2e38ffe 100644
--- a/internal/class.h
+++ b/internal/class.h
@@ -69,7 +69,7 @@ struct RClass {
     struct RBasic basic;
     VALUE super;
     struct rb_id_table *m_tbl;
-#if SIZE_POOL_COUNT == 1
+#if !RCLASS_EXT_EMBEDDED
     struct rb_classext_struct *ptr;
 #endif
 };