No such node or ancher

[excalamus]

I'm trying to create an @xref to an @anchor.  When clicking the reference, 
Emacs says,

"No such node or anchor: x-spot"

I have taken the sample file from (texinfo) Short Sample Texinfo File and 
copied the anchor example given in (texinfo) @anchor.  I put the anchor command 
in Chapter 1 and the reference in the Index.  makeinfo complains about no 
VERSION or UPDATED flags, but is otherwise silent.  Clicking on the reference 
takes me to Top and displays the error message.  I would expect it to take me 
to the anchor.  Am I doing something wrong?

\input texinfo
@settitle Sample Manual 1.0

@copying
This is a short example of a complete Texinfo file.

Copyright @copyright{} 2016 Free Software Foundation, Inc.
@end copying

@titlepage
@title Sample Title
@page
@vskip 0pt plus 1filll
@insertcopying
@end titlepage

@c Output the table of the contents at the beginning.
@contents

@ifnottex
@node Top
@top GNU Sample

This manual is for GNU Sample
(version @value{VERSION}, @value{UPDATED}).
@end ifnottex

@menu
* First Chapter::    The first chapter is the
                    only chapter in this sample.
* Index::            Complete index.
@end menu


@node First Chapter
@chapter First Chapter

@cindex chapter, first

This is the first chapter.
This marks the @anchor{x-spot}spot.
@cindex index entry, another

Here is a numbered list.

@enumerate
@item
This is the first item.

@item
This is the second item.
@end enumerate


@node Index
@unnumbered Index

@xref{x-spot,,the spot}.

@printindex cp

@bye