Or, weigh the cost and worry of a repair against the cost of another neck. Either way, do something. That won't stay unbroken long. And it is almost certain to break at a gig because, well, everything always does.
Forgot to say...MY first choice would be to replace it. Then I would try to repair the broken neck knowing that my gigging guitar was fine.
Gorilla glue rocks. I don’t know why you guys keep bagging on it
Yes, titebond wood glue. If you can move it ever so slightly and carefully to open up the crack a little more, syringe some glue up in there, so much it comes out other areas. Wipe excess off with a damp rag. Clamp with a good hand clamp, and let sit. That joint will be the strongest part of the neck. And if you believe Kirk Hammet....well.... you know it’ll sound better.