The Battle of Algiers

Well, since this is an older film, the trailer music MIGHT actually come from the film's soundtrack - plus it's a smaller independant release, meaning they're less likely to use their budget on licensing outside music for use in their campaign... But this is just all speculation on my part. You should really email the studio releasing the film and ask them about it. Since it's a smaller release/studio, you're more likely to get a response from them.