hash.c: env_str_transcode

* hash.c (env_str_transcode): convert with replacing invalid/undef
  characters, on Windows.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46544 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-06-25

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46545 b2dd03c8-39d4-4d8f-98ff-823fe69b080e