Initially suggested [here](https://github.com/think-cell/tcjs/pull/1#issuecomment-633575840). Things to check * [ ] Bugs can be induced by adding `class std{}`/`class js_defs{}`/`class jst {}` or similar inside TypeScript global library. * [ ] What namespaces are affected by the generated code * [ ] Whether generated code itself uses full global qualification
