By Bonnie Stiernberg There are countless hours of footage of Prince performing and giving interviews that were recorded throughout his legendary career. But footage of the late musician as a young boy growing up in Minneapolis is much harder to come by, which makes a newly unearthed clip all the more exciting. Last month, while looking through archival footage from stories about a 1970 teachers strike to accompany a new report about a present-day work stoppage, producers at Minneapolis’s WCCO stumbled upon a brief clip of an 11-year-old Prince being interviewed by the station about the strike….