Can’t query status.

OS X doesn’t seem to like `${glibcLocales}`.

```
$ nix-env -qa --status --show-trace                       
error: while evaluating the attribute ‘LOCALE_ARCHIVE’ of the derivation ‘commonmark-31b7bb562a97fe9fefbeb4c7129d050b81b408e2’ at /Users/greg/Documents/sources/idrispkgs/default.nix:14:7:
cannot coerce null to a string, at /Users/greg/Documents/sources/idrispkgs/default.nix:18:25
```
