Dan Rae, the reporter and broadcaster best known for his WBZ radio show NightSide, has made a “substantial” gift to UMass Boston to “renovate and endow the weight room” in the Clark Athletic Center. Rea is a 1970 graduate of Boston State College, which later merged with UMass Boston, and a member of the university’s Hall of Fame.The 3,300-square-foot space on the Dorchester