Angola's independence party is less incompetent/Communist, actually manages to keep most of its skilled labor within the country. Carnation Revolution goes bad, and although Portugal doesn't go Communist, there is a short civil war and a huge recession.
Over the years, as Angola develops with American investment, Portuguese begin moving to Angola. White Mozambicans also flee to Angola as that country goes to hell (and possibly the same with Bissau). Portuguese emigration temporarily stops once their economy improves.
In the mid-2000s, the world has an alt-Great Recession. Angola has developed its material resources to such a degree that their economy weathers it better than Europe. Spaniards, Portuguese and Italians all move to Angola, which has become the biggest economy in sub-Saharan Africa.
Other possibilities include people moving to South Africa. Brazil could also count, insofar as it is very multiracial.