GLOBAL MARKETS-Oil below $80 as slow China chimes with OPEC warning

* Brent crude at 4-year low as Saudis aloof on output cuts* European shares recover 0.4 pct after falls on Wednesday* Dollar near seven-year high vs yenBy Marc JonesLONDON, Nov 13 (Reuters) - Oil fell below $80 a barrel for the first time since 2010 on Thursday, as more evidence of a slowdown in China&aposs resource-hungry economy chimed with OPEC warning of a substantial drop in demand next year.