frame in the block.

* file.c (rb_file_s_expand_path): may overrun buffer on stack.

* regex.c (re_search): should consider reverse search.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_6@1613 b2dd03c8-39d4-4d8f-98ff-823fe69b080e