Instructions to build dmd under Windows are broken

## Walter Bright (@WalterBright) reported this on 2024-01-20T07:51:43Z

### Transferred from https://issues.dlang.org/show_bug.cgi?id=24347

### Description

````markdown
The page

https://wiki.dlang.org/Building_under_Windows

is now wrong because of

https://github.com/dlang/dmd/pull/15894
````