treat a write to a union field as an initialization of the entire union for the purposes of liveness. Also fix a bug with global vars in my last checkin
treat a write to a union field as an initialization of the entire union for the purposes of liveness. Also fix a bug with global vars in my last checkin

samuelhavron/obliv-c,samuelhavron/obliv-c,samuelhavron/obliv-c,samuelhavron/obliv-c