I don't think any of the directives mention in the [docs](https://github.com/nim-lang/c2nim/blob/master/doc/c2nim.rst) could be helpful in your case. Maybe edit the generated file by hand and change it to cstring/string.
- c2nim problem with char[] to UncheckardArray[char] alexgustafson
- c2nim problem with char[] to UncheckardArray[char] planetis
- c2nim problem with char[] to UncheckardArray[char] alexgustafson
