I'm surprised you're having issues with this in iOS 7, as they handle spanning the meridian better than prior versions. In iOS 7, the following:
CLLocationCoordinate2D coordinates[3];
coordinates[0] = CLLocationCoordinate2DMake(0, -170);
coordinates[1] = CLLocationCoordinate2DMake(0, 170);
coordinates[2] = CLLocationCoordinate2DMake(10, 180);
MKPolygon *polygon = [MKPolygon polygonWithCoordinates:coordinates count:3];
[self.mapView addOverlay:polygon];
produces (assuming you implement the typical rendererForOverlay
):
Doing this in prior iOS versions, it may not handle this properly, but in iOS 7, you should be fine. If you are still having issues, perhaps you can share how you've generated this polygon.