If there are multiple targets in a cmake project, how to set different args for each target?

```
"cmake.debugConfig": {
"args": [
"-c",
"/path/to/cfgfile"
]
}
```

_Originally posted by @bobbrow in https://github.com/microsoft/vscode-cmake-tools/issues/121#issuecomment-887070667_

The issue only identifies the cmake.debugConfig setting and provides no source file or test. Start by locating the configuration handling for cmake.debugConfig and how selected targets are passed to debugging. Done should mean that separate targets can receive distinct debug arguments, with the behavior documented or covered by a test.

Written by the indexing model from the issue text.