This patch ensures that '-target' can be used to set the 'simulator' environment component in the target triple.
Can we hold off on the warning and try to add that separately in the future? It would be good to first find out how often this code is being used. If there are a lot of uses, we may need to try to get people to stop relying on it before we add the warning. (I'm concerned about -Werror breaking builds with this.)