Imports of package riscv64

PathSynopsis
cmd/internal/obj/riscvPackage riscv implements the riscv64 assembler.
cmd/internal/objabi
cmd/internal/sys
cmd/link/internal/ld
cmd/link/internal/loader
cmd/link/internal/sym
debug/elfPackage elf implements access to ELF object files.
fmtPackage fmt implements formatted I/O with functions analogous to C's printf and scanf.
logPackage log implements a simple logging package.
sortPackage sort provides primitives for sorting slices and user-defined collections.