* hash.c (env_enc_str_new): as no locale/filesystem encoding is
available in miniruby on Windows, fallback the encoding to
ASCII-8BIT so it is valid encoding when the conversion failed.
[ruby-core:89177] [Bug #15164]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64860 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
