1: move / split usercopy.c to / into arch-specific library
2: move mem{cpy,set}.S to arch-specific library
3: move {clear_,copy_,scrub-}page.S to arch-specific libraryJan
1: move / split usercopy.c to / into arch-specific library
2: move mem{cpy,set}.S to arch-specific library
3: move {clear_,copy_,scrub-}page.S to arch-specific libraryJan