// swift-tools-version:4.0
import PackageDescription

var targets:[Target] = [
    .target(name: "OnlinePlayground")
]

var products: [Product] = [
    .library(name: "OnlinePlayground", targets: ["OnlinePlayground"])
]

let package = Package(
    name: "Foofooo",
    products: products,
    dependencies: [],
    targets: targets
)

$ swift build --product OnlinePlayground
Fatal error: file /BuildRoot/Library/Caches/com.apple.xbs/Sources/swiftpm/swiftpm-13752/Sources/Build/llbuild.swift, line 235
Illegal instruction: 4

$ swift build
Compile Swift Module 'OnlinePlayground' (1 sources)