Broccoli plugin fails to build with a fresh new application

[fr0gs]

``

my-app@0.0.0 start /home/esteban/gits/test/my-app ember server

Could not start watchman Visit https://ember-cli.com/user-guide/#watchman for more info. Livereload server on http://localhost:49153 The Broccoli Plugin: [BroccoliMergeTrees] failed with: SyntaxError: Block-scoped declarations (let, const, function, class) not yet supported outside strict mode at exports.runInThisContext (vm.js:53:16) at Module._compile (module.js:373:25) at Object.Module._extensions..js (module.js:416:10) at Module.load (module.js:343:32) at Function.Module._load (module.js:300:12) at Module.require (module.js:353:17) at require (internal/module.js:12:17) at Project.require (/home/esteban/gits/test/my-app/node_modules/ember-cli/lib/models/project.js:322:14) at Project.targets (/home/esteban/gits/test/my-app/node_modules/ember-cli/lib/models/project.js:238:28) at RollupWithDependencies.build (/home/esteban/gits/test/my-app/node_modules/@glimmer/application-pipeline/dist/lib/broccoli/rollup-with-dependencies.js:64:38)

The broccoli plugin was instantiated at: at BroccoliMergeTrees.Plugin (/home/esteban/gits/test/my-app/node_modules/broccoli-plugin/index.js:7:31) at new BroccoliMergeTrees (/home/esteban/gits/test/my-app/node_modules/broccoli-merge-trees/index.js:16:10) at GlimmerApp.package (/home/esteban/gits/test/my-app/node_modules/@glimmer/application-pipeline/dist/lib/broccoli/glimmer-app.js:256:23) at GlimmerApp.toTree (/home/esteban/gits/test/my-app/node_modules/@glimmer/application-pipeline/dist/lib/broccoli/glimmer-app.js:287:28) at module.exports (/home/esteban/gits/test/my-app/ember-cli-build.js:10:14) at Builder.setupBroccoliBuilder (/home/esteban/gits/test/my-app/node_modules/ember-cli/lib/models/builder.js:56:19) at new Builder (/home/esteban/gits/test/my-app/node_modules/ember-cli/lib/models/builder.js:30:10) at ServeTask.run (/home/esteban/gits/test/my-app/node_modules/ember-cli/lib/tasks/serve.js:24:55) at /home/esteban/gits/test/my-app/node_modules/ember-cli/lib/models/command.js:243:46 at tryCatch (/home/esteban/gits/test/my-app/node_modules/rsvp/dist/rsvp.js:525:12)

My ember-cli, npm and nodejs versions are:

```sh
my-app:master* λ npm -v
5.3.0
my-app:master* λ ember -v
ember-cli: 2.14.1
node: 4.8.4
os: linux x64

This can be fixed just by adding 'use strict'; on top of config/targets.js

[rwjblue]

Would love a PR adding the required use strict line, you would fix it over in glimmerjs/glimmer-blueprint.

[fr0gs]

You got it https://github.com/glimmerjs/glimmer-blueprint/pull/60/files