I'm probably a little OCD with the unanswered questions. Is there any point in answering questions where the comments seem to have been good enough for the OP and that haven't received any further attention ?
Your links point to questions that were asked and then answered by comments. The OP (presumably satisfied) abandoned the question.
These questions should be answered. This can be done by taking the comments and wrapping them into a lucid answer. It makes the site a better source of information because the visitor does not have to pick and pluck through a comment trail. We should encourage it.
Moreover, there is nothing wrong or unprofessional with wrapping other people's comments into an answer. It's the SO model and this aging scribe remembers seeing commentary from Jeff Atwood to that effect.
And finally, this type of question is low-hanging fruit for a contributor seeking to big up his/her reputation score. It's a win-win situation, the contributor gets rep and the site is better presented. Senior contributors should upvote when they spot someone doing this.
What Gayot suggests has to be the recommended option - ie create a good answer even if heavily reliant of information (hopefully attributed) from others. However if there is nothing more to say (except waffle) or the answerer lacks expertise to contribute further, then just copy the entire Comment or Comments into an answer. That will include appropriate attribution. Comments are "second class citizens" and may be deleted without trace (for other than mods) at any time. Answers are less vulnerable to loss.
When I take this approach I try to remember to make the A a wiki one. As a 'housekeeping' function I do not consider it deserves up or down votes for the answerer.