I also think it would make sense to include it in the upstream source. I'm a bit puzzled by the assertion that the GPL is incompatible with the MIT license. Its not incompatible, unless someone is thinking that they want to redistribute bitcoin, and the man page, under a more restrictive license for some purpose. Which MIT permits, but GPL does not. For what purpose would someone want to restricting users' rights?
Sorry, I suppose I wasn't clear there. I didn't mean that its incompatible ie not possible, but that it is incompatible ie of a more restrictive license and thus wouldn't be committable to the Bitcoin repo. Without wanting to get into the intricacies of FLOSS licensing, Bitcoin is MIT for a reason, and GPL isnt committable.