Right, adding `"LC_ALL" => nil` will satisfy the condition of `args[:environment].has_key?("LC_ALL")`. For example, you could do:

```ruby
run_opts[:environment] = {"LC_ALL" => ENV["LC_ALL"]}
```

This will preserve `LC_ALL` if it's already set in the user's environment. If it's not set, then `ENV["LC_ALL"]` returns nil, which should prevent `popen4` from changing it to "C".