Tip O’Neill, the legendary Democrat whose legacy is defined as much by his bipartisanship efforts as by the federal dollars he landed to build the Big Dig, would have turned 100 this year and his birthday (Dec. 9, 1912) was celebrated a little early on Thursday by family, faculty, and alumni at Boston College. During his time as the 55th speaker of the House of Representatives between 1977 and 1987, O’Neill, who was from North Cambridge, raised money for the construction of his alma mater’s library, and created the Thomas P. O’Neill Jr. Scholarship Fund, through which $5 million in scholarships have been awarded to more than 300 BC students. In attendance Thursday were the Rev. J. Donald Monan, chancellor of Boston College; Shep Melnick, the O’Neill Professor of American Politics at BC; author Thomas Mann, senior fellow at the Brookings Institute and noted congressional scholar; and two of O’Neill’s four surviving children, daughter Susan O’Neill and son Thomas P. O’Neill III.