As I understand it, in recent years many turkey hunters have had lions come in on them after calling. Last spring season, the Oregon NWTF state president got attacked by one while he was turkey hunting. Maybe if you're expecting one, you could try a turkey call?
Personally I'd be very leary of the approach. Having a turkey come up behind you is one thing. Having a big cat do the same thing is an other story.

Good luck & be safe whatever you decide to do.