t.Parallel()
	// issue 10139
	switch runtime.GOOS {
	case "plan9", "windows":
		t.Skipf("no pthreads on %s", runtime.GOOS)
	}

	got := runTestProg(t, "testprogcgo", "CgoExternalThreadSignal")
	if want := "OK\n"; got != want {
		if runtime.GOOS == "ios" && strings.Contains(got, "C signal did not crash as expected") {
			testenv.SkipFlaky(t, 59913)
		}