merges r22275 from trunk into ruby_1_9_1.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@22534 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merges r22275 from trunk into ruby_1_9_1.
instead of vm_get_ruby_level_caller_cfp(). checking a upper frame
is not enough. [ruby-dev:37984]
on vm_core.h.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@22534 b2dd03c8-39d4-4d8f-98ff-823fe69b080e