Consider default `$(RuntimeIdentifier)` for MacCatalyst apps?

[jonathanpeppers]

Steps to Reproduce

1. dotnet new maccatalyst
2. dotnet build or dotnet build -c Release

Even on an M1, I get a maccatalyst-x64 app.

Expected Behavior

I'm thinking it should do:

1. Debug - pick the RID on the machine you're building with. So an M1 gets a maccatalyst-arm64 and Intel gets maccatalyst-x64, and this would help the developer loop? No Rosetta when your app launches for debugging/development?
2. Release - defaults to RuntimeIdentifiers=maccatalyst-x64;maccatalyst-arm64 so Release builds get an app that supports both by default.

Users can override these defaults in their .csproj.

Actual Behavior

It seems like it just defaults to maccatalyst-x64? Always?

Environment

I was testing with the latest .NET 6 builds.

[chamons]

This seems like a good idea, adding to NET7 for consideration.

FYI @dalexsoto @rolfbjarne

[jonathanpeppers]

This might also apply to net6.0-macos apps, but I didn't try one of those. I was testing MacCatalyst for a customer's MAUI app.

[spouliot]

This might also apply to net6.0-macos apps,

Yes, I can confirm that this is the behaviour for net6.0-macos too.

IIRC @rolfbjarne wanted to ensure consistent output whatever the arch of the bots that build the app. The same logic would also apply to Catalyst apps.

[jonathanpeppers]

For now (maybe for .NET 7), I would consider just changing the default for Release builds and leave Debug builds as-is.

[rolfbjarne]

I agree, I'll make Release builds default to be universal (for both macOS and Mac Catalyst).

[rolfbjarne]

This is fixed now.