* Sitaram Chamarty:
It would seem to me that, if you changed them significantly, and going
by the above logic, you don't need to do *anything* regarding
attribution.
Note that applicable laws may impose additional restrictions, like
crediting authors in the way they require.
My personal approach is to include the copyright header of the file
I'm quoting from, together with a comment which explains where the
code came from (project, version, path).