changebars or other difference-highlighting tools for texinfo

[Jim Meyering]

Is there a tool to take two .texi files, compare them, and generate
a new .texi file containing mark-up to highlight the differences?

Something like texdiff <http://www.robmar.net/TexDiff/texdiff.pl.txt>
(a latex-oriented tool) would be nice.  Though I don't expect to find
color support in texinfo tomorrow :)