@Seth, I just did a quick grep of the KiCad source code and there are quite a few other places where we are using isdigit() to test a wxString character which will be a wxUniChar in unicode builds.
@Seth, I just did a quick grep of the KiCad source code and there are quite a few other places where we are using isdigit() to test a wxString character which will be a wxUniChar in unicode builds.