Some big boars can get "rank". That's how we refer to the condition here. They get a strong odor as a result of some type of hormone condition.
No doubt has to do with the mating process similar to deer or elk. If it's bad, you can smell it from a long ways off if down wind. When you smell that, a subsistence hunter will just let it walk.
I'm guessing here, but people generally don't give away meat unless they don't want it, or don't like it. If they are willing to give it to you it's probably not all that great. If the boar is rank you'll know it when it thaws out, you won't have to hold it to your nose either.
On the other hand if they didn't cook it right then they just think it's not good and in that case it may be worth your time.
At any rate, I wouldn't invite a bunch of friends over and I would have a backup plan for dinner that night just in case.
I agree with storm56 to an extent, overcooking meat, especially deer can really ruin it. But since this is a pig, and a wild one at that, it should be thoroughly cooked because of the parasites it can harbor, and they can be some bad ones. You don't want brucellocis or trichinosis or anything else, so cook it thoroughly. Wild pig, unlike domestic pig have a much stronger imune system but they don't get vaccinated ether, so cook it until it's done.
Having said that, you need to understand that the meat, if very lean, is going to get dry. If it has a lot of fat, cooking it until well done or 160-180F is not going to matter it will be moist.
If it's lean then you have to add something to give it moisture so use fruits and vegetables and have lots of liquid in the pan while roasting. I have cooked it just about everything you can think of including peaches and sprite yes Sprite the beverage. Beer is good for adding liquid and what ever vegetables you like in particular. These should go in within an hour of when the meat is done so they don't get too overcooked, unless you like them that way. I suggest the last hour with the vegetables, the meat should be covered.
Do not expect this to look like or taste like a beef rib roast or prime rib. Think of it more like a pot roast and it that will be your best bet.
good luck and keep us informed.
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001623/