NAIROBI, Sept 12 (Reuters) - The following company announcements, scheduled economic indicators, debt and currency market moves and political events may affect African markets on Friday. - - - - - EVENTS: SOUTH AFRICA - Treasury holds its weekly auction of inflation linked bonds. SOUTH AFRICA - Treasury holds weekly auction for 3-month, 6-month 9-month and 1-year treasury bills . GLOBAL MARKETS The U.S. dollar was riding high in Asia on Friday as unending speculation about