Add machine flag to our build.dart

lib/component_build.dart

Index: lib/component_build.dart
diff --git a/lib/component_build.dart b/lib/component_build.dart
index f5d6e848e523f6e63535391032aabc8f746fdc2a..9b972d37e2c891cefe69d0503449cd4d7206fec1 100644
--- a/lib/component_build.dart
+++ b/lib/component_build.dart
@@ -98,6 +98,8 @@ ArgResults _processArgs(List<String> arguments) {
     ..addOption("removed", help: "the file was removed since the last build",
         allowMultiple: true)
     ..addFlag("clean", negatable: false, help: "remove any build artifacts")
+    ..addFlag("machine", negatable: false,
+        help: "produce warnings in a machine parseable format")
     ..addFlag("help", negatable: false, help: "displays this help and exit");
   var args = parser.parse(arguments);
   if (args["help"]) {