Allergan Inc. is in talks to acquire Salix Pharmaceuticals Ltd., reviving discussions that began in July in an effort to fend off a hostile takeover offer from Valeant Pharmaceuticals International Inc., people with knowledge of the matter said. The Botox-maker's talks with Salix went dormant for a few weeks because Salix wanted a higher price than Allergan wanted to pay, said the people, who asked not to be identified discussing private information.