If I'm singing an old song that has content that might be perceived by some of the audience as "non-PC", I usually preface it with a remark that it was written some time ago when things were different, and explain the historical and/or social context if necessary, to pre-empt any outraged reaction from any "PC brigade" types who might be present. I find that usually works.

I guess if I was recording such a song I would just put something in the sleeve notes to similar effect, but what I wouldn't do is change the words to appease the PC brigade.

(But then I hate the term "PC" anyway, as it presupposes the views expressed in PC terms are "correct" - I don't always agree that's the case.)