You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: deps_test.go
    path of file: ./repos/gccrs/libgo/go/go/build
    
    the code of the file until where you have to start completion: // Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// This file exercises the import parser but also checks that
// some low-level packages do not have new dependencies added.

package build

import (
	"bytes"
	"fmt"
	"go/token"
	"internal/testenv"
	"io/fs"
	"os"
	"path/filepath"
	"runtime"
	"sort"
	"strings"
	"testing"
)

// depsRules defines the expected dependencies between packages in
// the G
    
func listStdPkgs(goroot string) ([]string, error) {
	// Based on cmd/go's matchPackages function.
	var pkgs []string

	src := filepath.Join(goroot, "src") + string(filepath.Separator)
	walkFn := func(path string, d fs.DirEntry, err error) error {
		if err != nil || !d.IsDir() || path == src {
			return nil
		}

		base := filepath.Base(path)
		if strings.HasPrefix(base, ".") || strings.HasPrefix(base, "_") || base == "testdata" {
			return filepath.SkipDir
		}

		name := filepath.ToSlash(path[len(src):])
		if name == "builtin" || name == "cmd" {
			return filepath.SkipDir
		}

		pkgs = append(pkgs, strings.TrimPrefix(name, "vendor/"))
		return nil
	}
	if err := filepath.WalkDir(src, walkFn); err != nil {
		return nil, err
	}
	return pkgs, nil
}