I'm still not sure about the reason of the issue, but I discovered that you can't include binaries in a Swift Package.This is the correct Package.swift:// swift-tools-version:5.1 // The swift-tools-version declares the minimum version of Swift required to build this package. import PackageDescription let package = Package( name: "MyLibrary", products: [ // Products define the executables and libraries produced by a package, and make them visible to other packages. .library( name: "MyLibrary", targets: ["MyLibrary"]), ], dependencies: [], targets: [ // Targets are the basic building blocks of a package. A target can define a module or a test suite. // Targets can depend on other targets in this package, and on products in packages which this package depends on. .target( name: "MyLibrary", dependencies: [], path: "Sources/MyLibrary", linkerSettings: [ .linkedFramework("Security"), .linkedLibrary("pthread"), .linkedLibrary("crypto"), .linkedLibrary("ssl") ]), ], cxxLanguageStandard: CXXLanguageStandard.cxx14 )I then placed the binaries in a directory and added the directory to the 'Library search paths' in Project->Build Settings