"weak" references internals, still needs perlguts documentation

(somewhat modified version of patch suggested by Tuomas J. Lukka
<lukka@fas.harvard.edu>)

p4raw-id: //depot/perl@3385

1 files changed, 3 insertions, 0 deletions

diff --git a/util.c b/util.c
index 8df5616573..56199d2fcc 100644
--- a/util.c
+++ b/util.c
@@ -3188,6 +3188,9 @@ get_vtbl(int vtbl_id)
     case want_vtbl_amagicelem:
 	result = &PL_vtbl_amagicelem;
 	break;
+    case want_vtbl_backref:
+	result = &PL_vtbl_backref;
+	break;
     }
     return result;
 }