* regcomp.c (optimize_node_left, set_optimize_info_from_tree): right
  handling for look behind anchor.

* regexec.c (onig_search): ditto.
  [Backport #8076]

this patch is derived from Onigmo base tree.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_3@39983 b2dd03c8-39d4-4d8f-98ff-823fe69b080e