const char trigs[] is an auto - it's allocated on the stack at function entry time - and must be initialized at each invocation. The literal used to do that is stored in globals space, which is why the globals allocation doesn't change.
static const char trigs[] is allocated in globals space and used in place. The symbols' scope is still local, though, so trigs[] isn't visible outside the function.
So why does code space increase by 52 bytes? That seems a lot for copying a string from place to another. So I'll take a guess that the need to copy a string loads a library module that includes it and a few other functions as well.