Ship non-threads and threads SDKs as a single SDK

[kateinoigakukun]

SwiftPM does not allow multiple targets within a single Swift SDK for now. There is no reason for the restriction and it forces us to distribute two SDKs for wasm32-unknown-wasip1-threads and wasm32-unknown-wasi.

[ephemer]

@finagolfin seems to have implemented multiple targets within the Android SDK, I'm curious whether that approach is accessible here?

[finagolfin]

Yeah, who says it's not allowed? The Musl static SDK bundle also supports multiple targets.

[kateinoigakukun]

The problem is even the format allows multiple targets, tools cannot uniquely select one of them when multiple SDK bundles containing multiple targets. See swiftlang/swift-package-manager#7973

[finagolfin]

OK, sure, that's a known bug, but it will only affect you if you're using the same target triple for threads and non-threads? Otherwise, why would you need multiple wasm SDK bundles anyway?

[kateinoigakukun]

it will only affect you if you're using the same target triple for threads and non-threads?

It could also be a problem if we are installing multiple versions of Wasm SDKs. We are frequently updating our SDK, so different branches in some code base can use different SDKs.