Swift build with foreign x86_64 library

I have a swift library that has worked for years and imports a foreign x86_64 C library. However, I recently replaced a broken iMac with an M2 Pro chip mac mini and I need to make some changes to the library. Now Xcode can't compile the package, saying it's ignoring the foreign library because it is not arm64 based. Moreover, if I try to compile with swift build it says it builds fine, but when I run swift test, it gives me a similar arm64 message.

Is there a way to fix this, both for xcode and raw swift? Both macOS and Xcode are latest versions.

Thanks in advance, Rick