> So if you use blank lines in any of your files, you are in blatant violation of AT&T's copyright claim

Independent derivation of a work is defense against copyright infringement.

Even if the copyright on these blank lines were to be valid, it would be reasonable to claim that your own use of blank lines was independent, not a derivative work copying from theirs.

Patents do not require actual copying to infringe, but copyright does. If you can prove you did not know of the original work, or otherwise would have come up with the same thing on your own, that's enough to absolve you of copyright issues.