Off-list (presumably accidentally), Gary R. Van Sickle replied:
I tend to think that the include guards should wrap as much of the file as
possible, idea being that the compiler then bypasses the most text
possible.
But then again, rumor has it that gcc (at least) recognizes such
constructs and
doesn't even rescan the file at all the second time, and scanning is
hardly the
bottleneck in gcc these days....
I don't think the extra copyright comments will have much of an effect on
compilation speed. I like the layout I proposed, because it gives increased
visual distinction between copyright boilerplate and file-specific
interesting info.