dfmt build never finished

[WebFreak001]

On Friday, 18 February 2022 at 18:10:43 UTC, Test123 wrote:
> Try build dfmt with ldc2, "dub" or "dub -b release" never 
> finished.
>
> [...]

it seems `rdmd` fails to run here.

Try editing the dub.json in dfmt and change the line
```
     "preGenerateCommands" : [
       "rdmd \"$PACKAGE_DIR/dubhash.d\""
     ]
```
to
```
     "preGenerateCommands" : [
       "dmd -run \"$PACKAGE_DIR/dubhash.d\""
     ]
```