JOHANNESBURG – South Africans are braced for a tight general election that may loosen the ANC’s 30-year hold on power — with many voters fed up with unemployment, crime and corruption.For a second day, 1.6 million “special voters” including the elderly, essential workers, police and prisoners, were allowed to cast their ballots early. The rest of South Africa’s 27-million-strong registered electorate will be called on Wednesday to elect provincial legislatures and a new national parliament. The latter then chooses the president. For the first time since the advent of democracy, the…