JOHANNESBURG/CAPE TOWN (Reuters) – General Motors suspended production at its main South African plant after a strike hit parts supplies, the U.S. automaker said on Friday, making it the latest victim of relentless labor unrest in Africa’s most advanced economy. Violence erupted on some picket lines, as the wage strike by the National Union of Metalworkers of South Africa (NUMSA) dealt a further blow to an economy damaged by a five-month walkout in the platinum industry that only ended last week.