Most of Africa will survive a nuclear war. But if history is anything to go by - Not South Africa. During the 80's Russia regarded South Africa as a unknown factor, but wanted to ensure safe passage around the Cape. The Suez and Panama Canals are stationary targets and would have been neutralised early in a full nuclear exchange. The ANC could not guarantee control of South Africa, so the Russia assigned the country its own strike package.
It targeted the harbours, military bases, seats of government and industrial facilities. Cape Town for one would have been hard hit, with the port, Simonstown Naval Base and Ysterplaat Airbase as targets. Same with Pretoria. Johannesburg would have been spared the brunt of it, but the country would have been bombed back to the stone age.
The question is if America has the same reasoning - seeing that South Africa is now closely partnered with Russia.