A non-vote is a non vote. That is all. This "non-vote = vote for the other guy" meme is, was, and always will be stupid and false. Abstention from voting adds nothing to anybody's vote total. What it means is that the abstainer sees no meaningful difference between the available (viable) candidates, and dislikes them both.
Now ... I can understand people disliking Trump. I can understand people disliking Hillary. I CAN'T understand anybody seeing no meaningful difference between them. That's just ignorant.
I'll be voting for Trump. I still think he's a pompous ass.