I don't like the official FAQ on bounties since it focuses on the answers and minutia.
You pay a bounty to get your question featured. That's what you get for the points.
If someone answers after the bounty - awesome. If you choose to award it to an existing question or choose to award it so that the system doesn't award half the bounty to whatever question gets 2 votes after the bounty started (or the most votes) - then you have that option.
If an answer helps you solve it - mark the tick for accepted. That way you can award the bounty or not as you feel best. Keep in mind - if you want to award more than one bounty, the next time you issue a bounty - the points will double, so you might award the initial 50 to one and leave the 100 to the one you feel deserves more rep bonus.
If you look at paying the bounty to feature the question - it seems to help most people decide how to dispose of the points once you reach the end of the period (since if you got an AWESOME answer that nailed your question you probably would award the bounty immediately since you were so happy to have your answer).
In the end - I usually award my bounty to the least bad answer and then decide I didn't do a good enough job writing the question to get the answer I wanted. I'll usually make a reminder in a week or two to revisit it, edit it and see if I want to try a bounty or let it ride.
In your case - HAVP is something that needs a pretty specific skill set to solve compilation errors (especially if you have any other OSS libraries installed or even not the same OSS libraries the developer of the package has on their system when they built that package) so it's a good thing you even got two answers in the short time frame that question has been around.