 private let whichArgs: [String] = ["xcrun", "--find"]
 #else
 private let whichArgs = ["which"]
+#endif
+#if os(Windows)
+private let hostExecutableSuffix = ".exe"
+#else
+private let hostExecutableSuffix = ""
 #endif
 
 /// Concrete object for manifest resource provider.

        self.swiftCompiler = swiftCompilers.compile

        // Look for llbuild in bin dir.
        llbuild = binDir.appending(component: "swift-build-tool")
        guard localFileSystem.exists(llbuild) else {
            throw InvalidToolchainDiagnostic("could not find `llbuild` at expected path \(llbuild)")
        }


    /// Path of the `swift` interpreter.
    public var swiftInterpreter: AbsolutePath {
        return swiftCompiler.parentDirectory.appending(component: "swift" + hostExecutableSuffix)
    }

    /// Path to the xctest utility.
