echo
echo
echo "1a) clean build using $FLAGS1"
(export GO_GCFLAGS="$FLAGS1"; sh make.bash)

echo
echo
echo "1b) save go build output for all packages"
for pkg in `go list std`; do
	echo $pkg
	DIR=$GOROOT/src/$pkg
	go build -gcflags "$FLAGS1 -S" -o /dev/null $pkg &> $DIR/old.txt
done

echo
echo
echo "2a) clean build using $FLAGS2"
(export GO_GCFLAGS="$FLAGS2"; sh make.bash)

echo
echo

// 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
		// to pass along "-gcflags="+os.Getenv("GO_GCFLAGS").
		// For now, if $GO_GCFLAGS is set, report that we simply can't
		// run go build.
		return false
	}

	goBuildOnce.Do(func() {

# GOHOSTARCH=386 on an amd64 machine.
#
# GOARCH: The target architecture for installed packages and tools.
#
# GOOS: The target operating system for installed packages and tools.
#
# GO_GCFLAGS: Additional go tool compile arguments to use when
# building the packages and commands.
#
# GO_LDFLAGS: Additional go tool link arguments to use when
# building the commands.
#

				// missing a C linker.
				t.Logf("HasGoBuild is false on %s", b)
				return
			}
		}

		if strings.Contains(b, "-noopt") {
			// 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)
	}

:: CGO_ENABLED: Controls cgo usage...

//   - ssa/all/time enables time reporting for all phases
//
// See gc/lex.go for dissection of the option string.
// Example uses:
//
// GO_GCFLAGS=-d=ssa/generic_cse/time,ssa/generic_cse/stats,ssa/generic_cse/debug=3 ./make.bash
//
// BOOT_GO_GCFLAGS=-d='ssa/~^.*scc$/off' GO_GCFLAGS='-d=ssa/~^.*scc$/off' ./make.bash
func PhaseOption(phase, flag string, val int, valString string) string {
	switch phase {
	case "", "help":

				}
				if err != nil {
					return err
				}
				cmd := testenv.Command(t, gotool, "build", "-buildmode=archive", "-o", cgoarchive, "-gcflags=all="+os.Getenv("GO_GCFLAGS"), "mycgo")
				cmd.Dir = filepath.Join(gopath, "src", "mycgo")
				cmd.Env = append(os.Environ(), "GOPATH="+gopath)
				out, err = cmd.CombinedOutput()
				if err != nil {

# GOHOSTARCH=386 on an amd64 machine.
#
# GOARCH: The target architecture for installed packages and tools.
#
# GOOS: The target operating system for installed packages and tools.
#
# GO_GCFLAGS: Additional go tool compile arguments to use when
# building the packages and commands.
#
# GO_LDFLAGS: Additional go tool link arguments to use when
# building the commands.
#

	"internal/testenv"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
	"testing"
	"time"
)

var globalSkip = func(t *testing.T) {}

var gcflags string = os.Getenv("GO_GCFLAGS")
var goroot string

func TestMain(m *testing.M) {
	flag.Parse()
	log.SetFlags(log.Lshortfile)
	os.Exit(testMain(m))
}

// tmpDir is used to cleanup logged commands -- s/tmpDir/$TMPDIR/
var tmpDir string

// or else the commands will rebuild any needed packages (like runtime)
// over and over.
func (test) goGcflags() string {
	return "-gcflags=all=" + os.Getenv("GO_GCFLAGS")
}

func (test) goGcflagsIsEmpty() bool {
	return "" == os.Getenv("GO_GCFLAGS")
}

var errTimeout = errors.New("command exceeded time limit")

// run runs the test case.
//