Merge pull request #1786 from chinmaygarde/master

Explicitly specify the sdk and arch when building for an iOS device

packages/flutter_tools/lib/src/ios/device_ios.dart

diff --git a/packages/flutter_tools/lib/src/ios/device_ios.dart b/packages/flutter_tools/lib/src/ios/device_ios.dart
index 08ac9e6..db509f8 100644
--- a/packages/flutter_tools/lib/src/ios/device_ios.dart
+++ b/packages/flutter_tools/lib/src/ios/device_ios.dart
@@ -532,7 +532,9 @@
     '/usr/bin/env', 'xcrun', 'xcodebuild', '-target', 'Runner', '-configuration', 'Release'
   ];
 
-  if (!isDevice) {
+  if (isDevice) {
+    commands.addAll(<String>['-sdk', 'iphoneos', '-arch', 'arm64']);
+  } else {
     commands.addAll(<String>['-sdk', 'iphonesimulator', '-arch', 'x86_64']);
   }