grc.Add(1)
	go func() {
		defer grc.Add(-1)
		gots <- wr.Get()
	}()
	clk.Run(nil)
	expectGotValue(t, gots, expected)
}

func expectGotValue(t *testing.T, gots <-chan interface{}, expected interface{}) {
	select {
	case gotVal := <-gots:
		t.Logf("Got %v", gotVal)
		if gotVal != expected {

		if strings.HasPrefix(line, goosPrefix) {
			inGOOS = true
		} else if inGOOS && strings.HasPrefix(line, "}") {
			break
		} else if inGOOS {
			goos := strings.Fields(line)[0]
			goos = strings.TrimPrefix(goos, `"`)
			goos = strings.TrimSuffix(goos, `":`)
			gooses = append(gooses, goos)
		}
	}

	for _, target := range gooses {
		if target == "nacl" {
			continue
		}
		var tags []string
		if target == "linux" {

}

// CgoSupported reports whether goos/goarch supports cgo.
func CgoSupported(goos, goarch string) bool {
	return distInfo[OSArch{goos, goarch}].CgoSupported
}

// FirstClass reports whether goos/goarch is considered a “first class” port.
// (See https://go.dev/wiki/PortingPolicy#first-class-ports.)
func FirstClass(goos, goarch string) bool {
	return distInfo[OSArch{goos, goarch}].FirstClass
}

	later := time.Now()
	bval := &later
	if wr.Set(bval) {
		t.Error("Set of initialized promise returned true")
	}
	goGetAndExpect(t, wr, gots, aval)
	cancel()
	time.Sleep(time.Second) // give it a chance to misbehave
	goGetAndExpect(t, wr, gots, aval)
}

func goGetExpectNotYet(t *testing.T, wr WriteOnce, gots chan interface{}, trigger string) {
	go func() {
		gots <- wr.Get()
	}()
	select {
	case <-gots:

	{name: "go/bin/go", goos: "linux"},
	{name: "go/bin/go", goos: "darwin"},
	{name: "go/bin/go", goos: "windows", exclude: true},
	{name: "go/bin/go.exe", goos: "windows"},
	{name: "go/bin/gofmt", goos: "linux"},
	{name: "go/bin/gofmt", goos: "darwin"},
	{name: "go/bin/gofmt", goos: "windows", exclude: true},
	{name: "go/bin/gofmt.exe", goos: "windows"},
	{name: "go/pkg/tool/*/compile", goos: "linux"},

}

func TestPidOf(t *testing.T) {
	if runtime.GOOS == "darwin" || runtime.GOOS == "windows" {
		t.Skipf("not supported on GOOS=%s", runtime.GOOS)
	}
	pids, err := PidOf(filepath.Base(os.Args[0]))
	assert.Empty(t, err)
	assert.NotZero(t, pids)
	assert.Contains(t, pids, os.Getpid())
}

func TestPKill(t *testing.T) {
	if runtime.GOOS == "darwin" || runtime.GOOS == "windows" {
		t.Skipf("not supported on GOOS=%s", runtime.GOOS)

	if CC != "" {
		return CC == want, nil
	}
	GOOS, _ := s.LookupEnv("GOOS")
	GOARCH, _ := s.LookupEnv("GOARCH")
	return cfg.DefaultCC(GOOS, GOARCH) == want, nil
}

func sysCondition(flag string, f func(goos, goarch string) bool, needsCgo bool) script.Cond {
	return script.Condition(
		"GOOS/GOARCH supports "+flag,
		func(s *script.State) (bool, error) {
			GOOS, _ := s.LookupEnv("GOOS")
			GOARCH, _ := s.LookupEnv("GOARCH")

stdout '"GO111MODULE": "auto"'
stdout '"CGO_CFLAGS": "nodefault"'
stdout '"CGO_CPPFLAGS": "nodefault"'

[GOOS:windows] env GOOS=linux
[!GOOS:windows] env GOOS=windows
[GOARCH:amd64] env GOARCH=arm64
[!GOARCH:amd64] env GOARCH=amd64

go env -changed GOOS
[GOOS:windows] stdout 'set GOOS=linux'
[!GOOS:windows] stdout 'GOOS=''windows'''
go env -changed GOARCH
[GOARCH:amd64] stdout 'set GOARCH=arm64|GOARCH=''arm64'''

The OS specific files for the new build system are located in the `${GOOS}`
directory, and the build is coordinated by the `${GOOS}/mkall.go` program. When
the kernel or system library updates, modify the Dockerfile at
`${GOOS}/Dockerfile` to checkout the new release of the source.

To build all the files under the new build system, you must be on an amd64/Linux
system and have your GOOS and GOARCH set accordingly. Running `mkall.sh` will

env GOENV=badenv
env GOOS=
env GOARCH=
env GOEXPERIMENT=

! go env
stderr '^go(\.exe)?: unknown GOEXPERIMENT badexp$'

go env -u GOEXPERIMENT

! go env
stderr '^go: unsupported GOOS/GOARCH pair bados/badarch$'

! go env -u GOOS
stderr '^go: unsupported GOOS/GOARCH pair \w+/badarch$'

! go env -u GOARCH
stderr '^go: unsupported GOOS/GOARCH pair bados/\w+$'

go env -u GOOS GOARCH