Adding `GC.compact` and compacting GC support.

This commit adds the new method `GC.compact` and compacting GC support.
Please see this issue for caveats:

  https://bugs.ruby-lang.org/issues/15626

[Feature #15626]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67479 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 1 deletions

diff --git a/iseq.h b/iseq.h
index feb73a82ae..9681d16f5f 100644
--- a/iseq.h
+++ b/iseq.h
@@ -234,7 +234,7 @@ struct iseq_catch_table_entry {
      *   CATCH_TYPE_REDO, CATCH_TYPE_NEXT:
      *     NULL.
      */
-    const rb_iseq_t *iseq;
+    rb_iseq_t *iseq;
 
     unsigned int start;
     unsigned int end;