}
	os.Setenv("CMDGO_TEST_RUN_MAIN", "true")

	// $GO_GCFLAGS a compiler debug flag known to cmd/dist, make.bash, etc.
	// It is not a standard go command flag; use os.Getenv, not cfg.Getenv.
	if os.Getenv("GO_GCFLAGS") != "" {
		fmt.Fprintf(os.Stderr, "testing: warning: no tests to run\n") // magic string for cmd/go
		fmt.Printf("cmd/go test is not compatible with $GO_GCFLAGS being set\n")
		fmt.Printf("SKIP\n")
		return
	}

	numberColonRe         = regexp.MustCompile(`^ *\d+:`)
)

var gdb = "gdb"      // Might be "ggdb" on Darwin, because gdb no longer part of XCode
var debugger = "dlv" // For naming files, etc.

var gogcflags = os.Getenv("GO_GCFLAGS")

// optimizedLibs usually means "not running in a noopt test builder".
var optimizedLibs = (!strings.Contains(gogcflags, "-N") && !strings.Contains(gogcflags, "-l"))

	"flag"
	"fmt"
	"io"
	"io/fs"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"reflect"
	"regexp"
	"runtime"
	"strconv"
	"strings"
	"time"
)

func cmdtest() {
	gogcflags = os.Getenv("GO_GCFLAGS")
	setNoOpt()

	var t tester

	var noRebuild bool
	flag.BoolVar(&t.listMode, "list", false, "list available tests")
	flag.BoolVar(&t.rebuild, "rebuild", false, "rebuild everything first")

	install("time/tzdata") // no dependency in sources; creates generated file
	install("cmd/go")
	if vflag > 0 {
		xprintf("\n")
	}

	gogcflags = os.Getenv("GO_GCFLAGS") // we were using $BOOT_GO_GCFLAGS until now
	setNoOpt()
	goldflags = os.Getenv("GO_LDFLAGS") // we were using $BOOT_GO_LDFLAGS until now
	goBootstrap := pathf("%s/go_bootstrap", tooldir)
	if debug {