git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_2@30039 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merges r29449 from trunk into ruby_1_9_2.¶
workaround of VC10's strerror() and sys_nerr problem.
based on a patch from Akio Tajima, [ruby-dev:42355].
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_2@30039 b2dd03c8-39d4-4d8f-98ff-823fe69b080e