auto-refresh TAGS file on ChangeLog mod?

[Ted Zlatanov]

I'm curious if there's a way to auto-run etags in a directory when I run
`find-tag' if the ChangeLog file (or any other file I specify) is newer
than the TAGS file.  In Makefile format, this is simply

TAGS: ChangeLog my-files-here
        etags file-list-here

or, for full interdependency

TAGS: ChangeLog file-list-here
        etags file-list-here

I didn't see anything relevant in the docs, so instead of writing it
myself I thought I'd check if anyone has done it before.

Thanks
Ted