Correct canImport

Author: grynspan

Sources/swift-test/Entrypoint.swift

@@ -18,9 +18,9 @@ private import Darwin.C
 @main
 struct Entrypoint {
     static func main() async throws {
+#if canImport(Darwin.C)
       // HACK: use the swift-test executable as a host for the .xctest bundle
       // when running Swift Testing tests.
-#if os(macOS) || os(iOS) || os(watchOS) || os(tvOS) || os(visionOS)
       let args = CommandLine.arguments
       if args.count >= 3, args[1] == "--test-bundle-path" {
         let bundlePath = args[2]