// and os.Stderr.
func (t *tester) dirCmd(dir string, cmdline ...interface{}) *exec.Cmd {
	bin, args := flattenCmdline(cmdline)
	cmd := exec.Command(bin, args...)
	if filepath.IsAbs(dir) {
		setDir(cmd, dir)
	} else {
		setDir(cmd, filepath.Join(goroot, dir))
	}
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	if vflag > 1 {
		errprintf("%s\n", strings.Join(cmd.Args, " "))
	}
	return cmd
}

// then the entire ecosystem of packages with that as a dependency had to
// explicitly update to the new version. Many packages depend on
// assume-no-moving-gc transitively, through paths like
// inet.af/netaddr -> go4.org/intern -> assume-no-moving-gc.
// This was causing a significant amount of friction around each new
// release, so we added this bool for the package to //go:linkname