How send parameters to DMD when using DUB

[ryuukk_]

And to reply to your original question

"How send parameters to DMD when using DUB"

It's easy:

```json
"dflags": [
     "-preview=rvaluerefparam"
],
```

For linker:

```json
"lflags": [
     "/SUBSYSTEM:windows",
     "/ENTRY:mainCRTStartup"
],
```