Specify a platform for each framework target. This fixes Carthage support
Specify a platform for each framework target.
This fixes Carthage support

cburrows/swift-protobuf,cburrows/swift-protobuf,thomasvl/swift-protobuf,cburrows/swift-protobuf,allevato/swift-protobuf,tbkka/swift-protobuf,tbkka/swift-protobuf,thomasvl/swift-protobuf,thomasvl/swift-protobuf,thomasvl/swift-protobuf,thomasvl/swift-protobuf,apple/swift-protobuf,tbkka/swift-protobuf,apple/swift-protobuf,allevato/swift-protobuf,thomasvl/swift-protobuf,allevato/swift-protobuf,allevato/swift-protobuf,apple/swift-protobuf,allevato/swift-protobuf,tbkka/swift-protobuf,apple/swift-protobuf,allevato/swift-protobuf,tbkka/swift-protobuf,apple/swift-protobuf,cburrows/swift-protobuf,cburrows/swift-protobuf,allevato/swift-protobuf,cburrows/swift-protobuf,tbkka/swift-protobuf,tbkka/swift-protobuf,thomasvl/swift-protobuf,apple/swift-protobuf,cburrows/swift-protobuf,apple/swift-protobuf