[mtouch] Only check for iOS min deployment target when building for iOS. (#1302)

tools/common/Assembly.cs

@@ -176,7 +176,7 @@ namespace Xamarin.Bundler {
 					path = Path.Combine (Cache.Location, libraryName);
 					if (path.EndsWith (".framework", StringComparison.Ordinal)) {
 #if MONOTOUCH
-						if (App.DeploymentTarget.Major < 8) {
+						if (App.Platform == Xamarin.Utils.ApplePlatform.iOS && App.DeploymentTarget.Major < 8) {
 							throw ErrorHelper.CreateError (1305, "The binding library '{0}' contains a user framework ({0}), but embedded user frameworks require iOS 8.0 (the deployment target is {1}). Please set the deployment target in the Info.plist file to at least 8.0.",
 								FileName, Path.GetFileName (path), App.DeploymentTarget);
 						}