I ran:
docker run swift:5.5-amazonlinux2 /bin/bash -c "swift --version"
And the output was:
Swift version 5.5.3 (swift-5.5.3-RELEASE)
Target: x86_64-unknown-linux-gnu
I also tried explicitly executing the Docker packaging command using a Swift 5.5.3 image:
docker run \
--rm \
--volume "$(pwd)/:/src" \
--workdir "/src/" \
swift:5.5.3-amazonlinux2 \
/bin/bash -c "swift build --product API -c release --static-swift-stdlib"
But got the same error (linking error).
Also, I've since removed Kitura's SwiftJWT completely — replacing it with Vapor's JWTKit — but the linking error persists.