I don't think Xcode will ever produce .a files for packages, only swift build does that.
Best recommendation I have would be to look up the invocation for producing it from swift build --vv and try to manually do something equivalent with the object files produced by Xcode.
Has anyone else looked at the CPU utilisation when the compiler is going through the SwiftSyntax build phase? I've just taken a look at the Xcode timeline and it only seems to be using one core per architecture. Here's the timeline for a clean build of one my frameworks (you'll notice that out of the 2m37s build time only about the last 10s is building my code, the rest is building Swift Macro dependencies).
Is there any sort of fix for this? Seems like if it properly utilised my M1 Ultra it would be less of a "did I make a mistake using Macros" situation 
Hey there, just wanted to let everyone know that since github finally released an image with Xcode 15.3, I released version 510.0.1 of swift-syntax-xcframeworks.
Improvements since last version include a smaller size (only a single 15.8 MB zip) that now contains both macOS and iOS simulator architectures, if it somehow happens that iOS is needed (as in some earlier posts here).
