Android: Add threaded rendering to advanced options

android/app/src/main/res/values/strings.xml

@@ -147,4 +147,6 @@
     <string name="main_activity_invalid_error">This BIOS image is invalid, or has already been imported.</string>
     <string name="main_activity_show_version_title">Version</string>
     <string name="main_activity_copy">Copy</string>
+    <string name="settings_gpu_thread">Threaded GPU Rendering</string>
+    <string name="settings_summary_gpu_thread">Uses a second thread for drawing graphics. Currently only available for the software renderer, but can provide a significant speed improvement, and is safe to use.</string>
 </resources>

android/app/src/main/res/xml/advanced_preferences.xml

@@ -35,6 +35,12 @@
         app:defaultValue="false"
         app:summary="@string/settings_summary_preload_image_to_ram"
         app:iconSpaceReserved="false" />
+    <SwitchPreferenceCompat
+        app:key="GPU/UseThread"
+        app:title="@string/settings_gpu_thread"
+        app:defaultValue="true"
+        app:summary="@string/settings_summary_gpu_thread"
+        app:iconSpaceReserved="false" />
     <SwitchPreferenceCompat
         app:key="GPU/PGXPVertexCache"
         app:title="@string/settings_pgxp_vertex_cache"