Question:What is the opinion on selling pork and alcohol in Darul-Kufr (non-muslim countries)?
Answer: It is Haram to do so by scholarly consensus.
However, the transaction (not the act of giving wine or pork) is valid IF a muslim sold it to a kaafir (any non-Muslim.) That is, the money has become the sellers property, but a sin has been committed in helping someone to do something Haram (such help is explicitly forbidden by the Quran - so beware, beware, beware...) A possible exception (I am not sure -- it needs a fatwa) is if he is sure that the kaafir wants to use the wine to make vinegar. This would probably be rare anyway.
This is according to Abu Hanifah. According to most scholars, however, the transaction is invalid also, because it involves buying something that has no value to a Muslim. That is, according to them the money received would be haram, just like interest charged from a muslim.
According to Abu Hanifah, the reason why the transaction is correct, is that this is not really a buying and selling transaction. Rather, what the muslim is doing is taking money that is allowed for him to take, except that he is bound by the protection agreement he entered by going to daar al-kufr as a visitor. This protection agreement means that he cannot take their money without their consent, or harm them in any way.
The general rule then, is that if a kaafir in Daar al-Kufr willingly gives you money, then you can take it, UNLESS it involves cheating (because this means he is not really willing). However, the way you achieve this willingness (without cheating) needs to be considered separately to see if there is a sin or not. If it involves handing out pork and wine, then it is obviously sinful. No scholar would say differently.
This and similar questions are often misunderstood by people reading advanced books without sufficient qualifications, so beware. The problem is that some words in Arabic such as "jaaza" often refer to how a transaction is viewed in court (i.e. is the contract valid or not?), not whether the perpetrator has committed a sin or not.
Keep these two basic rules of the religion in mind:
1. It is Haram to help ANYONE commit a sin. E.g. giving a kaafir pork to eat.
2. Just because a contract is Islamically enforceable, does not necessarily mean that no sin has been committed.
... and Allah knows best.