}

var (
	mu          sync.Mutex
	crawled     = make(map[string]bool)      // URL without fragment -> true
	neededFrags = make(map[urlFrag][]string) // URL#frag -> who needs it
)

var aRx = regexp.MustCompile(`<a href=['"]?(/[^\s'">]+)`)

// Owned by crawlLoop goroutine:
var (
	linkSources = make(map[string][]string) // url no fragment -> sources
	fragExists  = make(map[urlFrag]bool)
	problems    []string
)

	// See https://golang.org/issue/22858.
	out, err := exec.Command(swig, "-version").CombinedOutput()
	if err != nil {
		t.Skipf("failed to get swig version:%s\n%s", err, string(out))
	}

	re := regexp.MustCompile(`[vV]ersion +(\d+)([.]\d+)?([.]\d+)?`)
	matches := re.FindSubmatch(out)
	if matches == nil {
		// Can't find version number; hope for the best.
		t.Logf("failed to find swig version, continuing")
		return
	}

		if got := out.String(); text != got {
			t.Errorf("want full output %q, got %q", text, got)
		}
	}
	wantErr = regexp.MustCompile("^no exit code")
	check("abc")
	check("exitcode")
	check("exitcode=")
	check("exitcode=123\n")
	wantErr = regexp.MustCompile("^bad exit code: .* value out of range")
	check("exitcode=999999999999999999999999")