improve server bundle size

explicitly excluding nuxt's node_modules optimizes bundle size in both normal usage and when using in test/linked/npx

lib/builder/webpack/server.config.js

@@ -51,13 +51,19 @@ export default function webpackServerConfig () {
 
   // https://webpack.js.org/configuration/externals/#externals
   // https://github.com/liady/webpack-node-externals
-  if (existsSync(this.options.modulesDir)) {
-    config.externals.push(nodeExternals({
-      // load non-javascript files with extensions, presumably via loaders
-      whitelist: [/\.(?!(?:js|json)$).{1,5}$/i],
-      modulesDir: this.options.modulesDir
-    }))
-  }
+  const moduleDirs = [
+    this.options.modulesDir,
+    resolve(__dirname, '..', 'node_modules')
+  ]
+  moduleDirs.forEach(dir => {
+    if (existsSync(dir)) {
+      config.externals.push(nodeExternals({
+        // load non-javascript files with extensions, presumably via loaders
+        whitelist: [/\.(?!(?:js|json)$).{1,5}$/i],
+        modulesDir: dir
+      }))
+    }
+  })
 
   // --------------------------------------
   // Production specific config

lib/core/renderer.js

@@ -132,8 +132,9 @@ export default class Renderer extends Tapable {
     // Create bundle renderer for SSR
     this.bundleRenderer = createBundleRenderer(this.resources.serverBundle, Object.assign({
       clientManifest: this.resources.clientManifest,
-      runInNewContext: false,
-      basedir: this.options.rootDir
+      runInNewContext: false
+      // Explicitly setting basedir makes problems with linked nuxt and npx
+      // basedir: this.options.rootDir
     }, this.options.render.bundleRenderer))
 
     // Promisify renderToString