Short answer, no. SE will not have another system to mark "answered" questions that do not have an answer.
Now what to do in case like this one?
If a long time has passed since the "answer" comment, then just write an answer yourself. Give credit to the user that posted the comment, but feel free to actually answer the question, and make it better.
If it is one of these where the OP comes by at some point and says "never mind I did so and so, and it works now," then Vote to close it as "Too Localized" (close > off-topic because > Too Localized).
For this specific question, I closed it as a dup.
Lets say that it was not a duplicate, there is really only one thing left to do - answer it. There is no good comment to use as a source for an answer, so this answer would be new and totaly mine.
Now if you don't feel like writing an answer for the question, then there is nothing to be done to take it out of the unanswered list (because it is unanswered.)
Think of someone coming from google, they are not expected to dig through the comments to see what the OP did.
Answers should be in the answer section.