// 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

	"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 {