pt 1 in reviving the android build (copied from pm 28a1, wish me luck)

mobile/android/base/resources/xml/preferences_locale.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
+                  xmlns:gecko="http://schemas.android.com/apk/res-auto"
+                  android:title="@string/pref_category_language"
+                  android:enabled="false">
+    <PreferenceCategory android:title="@string/pref_browser_locale">
+        <!-- No title set here. We set the title to the current locale in
+             GeckoPreferences. -->
+        <org.mozilla.gecko.preferences.LocaleListPreference
+            android:key="locale"
+            android:persistent="true"
+            android:defaultValue=""
+        />
+    </PreferenceCategory>
+</PreferenceScreen>