Explicitly depend on System

Author: kabiroberai

tools/swift-plugin-server/Package.swift

@@ -9,6 +9,7 @@ let package = Package(
   ],
   dependencies: [
     .package(path: "../../../swift-syntax"),
+    .package(path: "../../../swift-system"),
     .package(path: "../../../wasmkit"),
   ],
   targets: [
@@ -17,6 +18,7 @@ let package = Package(
       dependencies: [
         .product(name: "SwiftCompilerPluginMessageHandling", package: "swift-syntax"),
         .product(name: "SwiftLibraryPluginProvider", package: "swift-syntax"),
+        .product(name: "SystemPackage", package: "swift-system"),
         .product(name: "WASI", package: "WasmKit"),
         .product(name: "WasmKitWASI", package: "WasmKit"),
       ]