diff --git a/vendor/golang.org/x/text/internal/language/compact/gen_index.go b/vendor/golang.org/x/text/internal/language/compact/gen_index.go
new file mode 100644
index 0000000..136cefa
--- /dev/null
+++ b/vendor/golang.org/x/text/internal/language/compact/gen_index.go
@@ -0,0 +1,113 @@
+// Copyright 2015 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.
+
+// +build ignore
+
+package main
+
+// This file generates derivative tables based on the language package itself.
+
+import (
+	"fmt"
+	"log"
+	"sort"
+	"strings"
+
+	"golang.org/x/text/internal/language"
+)
+
+// Compact indices:
+// Note -va-X variants only apply to localization variants.
+// BCP variants only ever apply to language.
+// The only ambiguity between tags is with regions.
+
+func (b *builder) writeCompactIndex() {
+	// Collect all language tags for which we have any data in CLDR.
+	m := map[language.Tag]bool{}
+	for _, lang := range b.data.Locales() {
+		// We include all locales unconditionally to be consistent with en_US.
+		// We want en_US, even though it has no data associated with it.
+
+		// TODO: put any of the languages for which no data exists at the end
+		// of the index. This allows all components based on ICU to use that
+		// as the cutoff point.
+		// if x := data.RawLDML(lang); false ||
+		// 	x.LocaleDisplayNames != nil ||
+		// 	x.Characters != nil ||
+		// 	x.Delimiters != nil ||
+		// 	x.Measurement != nil ||
+		// 	x.Dates != nil ||
+		// 	x.Numbers != nil ||
+		// 	x.Units != nil ||
+		// 	x.ListPatterns != nil ||
+		// 	x.Collations != nil ||
+		// 	x.Segmentations != nil ||
+		// 	x.Rbnf != nil ||
+		// 	x.Annotations != nil ||
+		// 	x.Metadata != nil {
+
+		// TODO: support POSIX natively, albeit non-standard.
+		tag := language.Make(strings.Replace(lang, "_POSIX", "-u-va-posix", 1))
+		m[tag] = true
+		// }
+	}
+
+	// TODO: plural rules are also defined for the deprecated tags:
+	//    iw mo sh tl
+	// Consider removing these as compact tags.
+
+	// Include locales for plural rules, which uses a different structure.
+	for _, plurals := range b.supp.Plurals {
+		for _, rules := range plurals.PluralRules {
+			for _, lang := range strings.Split(rules.Locales, " ") {
+				m[language.Make(lang)] = true
+			}
+		}
+	}
+
+	var coreTags []language.CompactCoreInfo
+	var special []string
+
+	for t := range m {
+		if x := t.Extensions(); len(x) != 0 && fmt.Sprint(x) != "[u-va-posix]" {
+			log.Fatalf("Unexpected extension %v in %v", x, t)
+		}
+		if len(t.Variants()) == 0 && len(t.Extensions()) == 0 {
+			cci, ok := language.GetCompactCore(t)
+			if !ok {
+				log.Fatalf("Locale for non-basic language %q", t)
+			}
+			coreTags = append(coreTags, cci)
+		} else {
+			special = append(special, t.String())
+		}
+	}
+
+	w := b.w
+
+	sort.Slice(coreTags, func(i, j int) bool { return coreTags[i] < coreTags[j] })
+	sort.Strings(special)
+
+	w.WriteComment(`
+	NumCompactTags is the number of common tags. The maximum tag is
+	NumCompactTags-1.`)
+	w.WriteConst("NumCompactTags", len(m))
+
+	fmt.Fprintln(w, "const (")
+	for i, t := range coreTags {
+		fmt.Fprintf(w, "%s ID = %d\n", ident(t.Tag().String()), i)
+	}
+	for i, t := range special {
+		fmt.Fprintf(w, "%s ID = %d\n", ident(t), i+len(coreTags))
+	}
+	fmt.Fprintln(w, ")")
+
+	w.WriteVar("coreTags", coreTags)
+
+	w.WriteConst("specialTagsStr", strings.Join(special, " "))
+}
+
+func ident(s string) string {
+	return strings.Replace(s, "-", "", -1) + "Index"
+}