Add /waitfordebugger argument to MGCB.

[dellis1972]

The call to System.Diagnostics.Debugger.Launch is
not supported on Unix based platforms. This makes
debugging MGCB.exe and Content Pipeline extensions
difficult.

So lets add a new argument which will make MGCB.exe
wait for a debugger to attach. Also add a extra
update to the launch.json to demonstrate how to
attach the dotnet debugger to an existing process.

This new system will also work on Windows.

To use this in VSCode you can add the following to the
launch.json

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Attach to Process",
            "type": "coreclr",
            "request": "attach",
            "processId": "${input.processid}",
        }
    ],
    "inputs": [
        {
            "id": "processid",
            "type": "promptString",
            "default": "0",
            "description": "Enter Process Id of process to attach to."
        }
    ]
}

you can then add the following to your csproj.

<MonoGameMGCBAdditionalArguments>/waitfordebugger</MonoGameMGCBAdditionalArguments>

This will cause the MGCB.exe to print the ProcessId
to the console during the build and wait for the debugger
to attach. Once you have the ProcessId you can run the
VSCode Attach to Process and enter the ProcessId when prompted.
The debugger should then attach.

If you want to prcess without attaching the debugger just hit any
key in the console or terminal windows where MGCB.exe is running.

[Akarinnnnn]

/d switch also seem to wait for debugger, too.

[dellis1972]

/d switch also seem to wait for debugger, too.

That switch will Launch Visual Studio on windows. It does nothing on MacOS/Linux.

[SimonDarksideJ]

Is the PR ready for re-review yet @dellis1972 ?

[dellis1972]

@SimonDarksideJ it is.

[SimonDarksideJ]

Looks good to me

[dellis1972]

ok gonna revert back to the new /waitfordebugger option as Debugger.Launch on windows only offers a VS option. VSCode or other IDE's are not supported 🤦 . So for VSCode / Rider to work we need to have a separate option