Update Android port

* java/org/gnu/emacs/EmacsContextMenu.java (display): Return
false if the list of menu buttons is empty, lest Android cease
displaying menus on the assumption that Emacs is defective.

* java/org/gnu/emacs/EmacsView.java (popupMenu): Likewise.

* src/fns.c (sort_list): Render sentence motion commands
functional within commentary

* src/sfntfont.c (sfntfont_list_family): Sort and deduplicate
the returned family list and make it a list of symbols.
(syms_of_sfntfont) <Qstring_lessp>: New defsym.

java/org/gnu/emacs/EmacsContextMenu.java

@@ -347,6 +347,13 @@ public final class EmacsContextMenu
     Runnable runnable;
     final EmacsHolder<Boolean> rc;
 
+    /* Android will permanently cease to display any popup menus at
+       all if the list of menu items is empty.  Prevent this by
+       promptly returning if there are no menu items.  */
+
+    if (menuItems.isEmpty ())
+      return false;
+
     rc = new EmacsHolder<Boolean> ();
     rc.thing = false;
 

java/org/gnu/emacs/EmacsView.java

@@ -622,6 +622,13 @@ public final class EmacsView extends ViewGroup
     if (popupActive && !force)
       return false;
 
+    /* Android will permanently cease to display any popup menus at
+       all if the list of menu items is empty.  Prevent this by
+       promptly returning if there are no menu items.  */
+
+    if (menu.menuItems.isEmpty ())
+      return false;
+
     contextMenu = menu;
     popupActive = true;