Would his trust found helped him to get where he is now?
Would he have trust found at all?
I don't think the comparison is whether certain regions have more access to wealth than others. That's a given. The question is, do some people in some regions have an unfair advantage over others, or is wealth the product of some individuals working harder and smarter to obtain it.
If Bill Gates was born in Africa, he probably would have tried to get an education in some American or European university (there were lots of people from Nigeria and other places in the universities I attended), and the end result may have still been similar, though it would have been harder for him to reach it.
I would say that he would likely not be in the same position as he is in now as he would almost certainly not have had access to the technology that was available in the US when he started Microsoft in africa, which would mean he could never have created windows/dos. I would say that the chances of him starting Microsoft would be even greater if his trust fund was the same size as "US" bill gates had because such a trust fund would be able to sustain a much better standard of living in africa and he would have no real incentive to work for a living and start any kind of a career