US STOCKS-Wall St set for flat open after manufacturing data
* Forest Labs surges after Actavis confirms acquisition
* Maker of Candy Crush files for U.S. IPO
* Futures up: Dow 21 pts, S&P 2.5 pts, Nasdaq 4 pts
By Angela Moon
NEW YORK, Feb 18 (Reuters) - Wall Street was set for a flat open on Tuesday after Wall Street posted its biggest weekly gain of the year, as data showed factory activity in New York state slowed this month.
* A New York Federal Reserve gauge of manufacturing was weaker than expected in February after hitting a 20-month high in January.
* U.S. stocks closed higher on Friday, with major indexes notching a second straight week of gains as investors shrugged off some weak economic data that was attributed to bad weather.
* U.S. markets were closed Monday for Presidents Day.
* Shares of Forest Laboratories Inc rocketed more than 35 percent in premarket trading after Actavis said it would acquire the specialty pharmaceuticals company in a massive cash and stock deal valued at about $25 billion. Continuación...