feat: production tip

packages/global.d.ts

@@ -1,4 +1,7 @@
 // Global compile-time constants
 declare var __DEV__: boolean
-declare var __COMPAT__: boolean
 declare var __JSDOM__: boolean
+
+// Feature flags
+declare var __FEATURE_OPTIONS__: boolean
+declare var __FEATURE_PRODUCTION_TIP__: boolean

packages/vue/src/index.ts

@@ -1,3 +1,10 @@
 // TODO this package will be the "full-build" that includes both the runtime
 // and the compiler
 export * from '@vue/runtime-dom'
+
+if (__FEATURE_PRODUCTION_TIP__) {
+  console[console.info ? 'info' : 'log'](
+    `You are running a development build of Vue.\n` +
+      `Make sure to use the production build (*.prod.js) when deploying for production.`
+  )
+}