nx_riscv_elf.nx

nx_riscv_elf.nx -- SOVEREIGN RISC-V backend RUNG 2: our own ELF64 writer. Now on the GENERAL nx_riscv_lib (shared build_header, encoders, byte readers, ident, UI) -- only the program + validation tests are local. T1 ELF written, size==144, magic/class(64)/data(LE). T2 e_machine=RISC-V(243), EXEC, e_flags=0(no-FPU), PT_LOAD R+X, entry. T3 our reader decodes the embedded code == [addi,addi,mul,addi,addi,ecall]. (no ld/readelf/sh) expect_exit: 0 Sovereign: nx_riscv_lib (+ nx_syscalls).