Conditionally allowing showCompass view property

Summary:
Only allow the showsCompass view property when iOS 9+ is used.  Fixes #5706.
Closes https://github.com/facebook/react-native/pull/5708

Reviewed By: svcscm

Differential Revision: D2896322

Pulled By: nicklockwood

fb-gh-sync-id: 16b789d3516ad1ff7189d6ceab4300039ce2a76b

React/Views/RCTMap.m

@@ -209,4 +209,17 @@ const CGFloat RCTMapZoomBoundBuffer = 0.01;
   self.overlayIDs = newOverlayIDs;
 }
 
+- (BOOL)showsCompass {
+  if ([MKMapView instancesRespondToSelector:@selector(showsCompass)]) {
+    return super. showsCompass;
+  }
+  return NO;
+}
+
+- (void)setShowsCompass:(BOOL)showsCompass {
+  if ([MKMapView instancesRespondToSelector:@selector(setShowsCompass:)]) {
+    super.showsCompass = showsCompass;
+  }
+}
+
 @end