To cry pork; to give intelligence to the undertaker of a funeral; metaphor borrowed from the raven, whose note sounds like the word pork. Ravens are said to smell carrion at a distance.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Poplers * PorkerNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes