[JIRA] (BIT-924) String BIFs Return 1-indexed string_arrays

Yeah, that sounds good. We could also add a command line flag that
statically checks for use of deprecated functionality so that people
don't only see it during runtime.

A slightly alternative approach would be CMake's policies, where one
can set (and eventually switch) a default value. But I've always found
that confusing because it's not just the cmake's version that
determines what's acceptable, but also the policy setting.