// The -noopt builder sets GO_GCFLAGS, which causes tests of 'go build' to
			// be skipped.
			t.Logf("HasGoBuild is false on %s", b)
			return
		}

		t.Fatalf("HasGoBuild unexpectedly false on %s", b)
	}

	t.Logf("HasGoBuild is true; checking consistency with other functions")

	hasExec := false
	hasExecGo := false
	t.Run("MustHaveExec", func(t *testing.T) {
		testenv.MustHaveExec(t)
		hasExec = true

// Builder returns the empty string.
func Builder() string {
	return os.Getenv("GO_BUILDER_NAME")
}

// HasGoBuild reports whether the current system can build programs with “go build”
// and then run them with os.StartProcess or exec.Command.
func HasGoBuild() bool {
	if os.Getenv("GO_GCFLAGS") != "" {
		// It's too much work to require every caller of the go command

	"internal/testenv"
	"internal/xcoff"
	"io"
	"os"
	"path/filepath"
	"runtime"
	"sync"
	"testing"
	"unicode/utf8"
)

var buildDir string

func TestMain(m *testing.M) {
	if !testenv.HasGoBuild() {
		return
	}

	exit := m.Run()

	if buildDir != "" {
		os.RemoveAll(buildDir)
	}
	os.Exit(exit)
}

func copyDir(dst, src string) error {
	err := os.MkdirAll(dst, 0777)
	if err != nil {

		if _, err := os.Stat("/etc/alpine-release"); err == nil {
			globalSkip = func(t *testing.T) { t.Skip("skipping failing test on alpine - go.dev/issue/19938") }
			return m.Run()
		}
	}
	if !testenv.HasGoBuild() {
		// Checking for "go build" is a proxy for whether or not we can run "go env".
		globalSkip = func(t *testing.T) { t.Skip("no go build") }
		return m.Run()
	}

	GOOS = goEnv("GOOS")
	GOARCH = goEnv("GOARCH")

	if err != nil {
		log.Fatal(err)
	}
	testTmpDir = dir
	if !*testWork {
		defer removeAll(testTmpDir)
	}

	testGOCACHE, _ = cache.DefaultDir()
	if testenv.HasGoBuild() {
		testBin = filepath.Join(testTmpDir, "testbin")
		if err := os.Mkdir(testBin, 0777); err != nil {
			log.Fatal(err)
		}
		testGo = filepath.Join(testBin, "go"+exeSuffix)
		gotool, err := testenv.GoTool()