Quickie junk code used to get around golang issue #21881

zone.go

package zonetools

import (
	"archive/zip"
	"bytes"
	"encoding/base64"
	"fmt"
	"io/ioutil"
	"regexp"
	"strings"
	"sync"
	"time"
)

var (
	lock       sync.RWMutex
	locs       = map[string]*time.Location{}
	prepared   bool
	prepareErr error
)

func prepare() {
	lock.Lock()
	defer lock.Unlock()
	prepared = true

	ptn := regexp.MustCompile(`\s+`)
	data := tzFiles["tz/zoneinfo.zip"]
	data = ptn.ReplaceAllString(data, "")
	decoder := base64.NewDecoder(base64.StdEncoding, strings.NewReader(data))
	bts, err := ioutil.ReadAll(decoder)

	if err != nil {
		prepareErr = err
		return
	}

	r, err := zip.NewReader(bytes.NewReader(bts), int64(len(bts)))
	if err != nil {
		prepareErr = err
		return
	}

	for _, f := range r.File {
		if f.FileInfo().IsDir() {
			continue
		}

		rc, err := f.Open()
		if err != nil {
			prepareErr = err
			return
		}
		fbts, err := ioutil.ReadAll(rc)
		if err != nil {
			rc.Close()
			prepareErr = err
			return
		}

		tz, err := time.LoadLocationFromTZData(f.Name, fbts)
		if err != nil {
			rc.Close()
			prepareErr = err
			return
		}
		rc.Close()

		locs[f.Name] = tz
	}
}

func LoadLocation(name string) (*time.Location, error) {
	lock.RLock()
	if !prepared {
		lock.RUnlock()
		prepare()
		lock.RLock()
	}
	defer lock.RUnlock()

	z := locs[name]
	if z == nil {
		return time.UTC, fmt.Errorf("zonetools: cannot find %q", name)
	}

	oz := *z
	return &oz, nil
}

// This code is dedicated to the public domain if such a concept 
// exists in your location, or licensed under the MIT license if not.

Line 28:
undefined: tzFiles