* kaem.riscv64: New file.
* lib/linux/riscv64-mes-m2/crt1.M1,
lib/m2/riscv64/ELF-riscv64.hex2,
lib/m2/riscv64/riscv64_defs.M1: New files, imported from M2Lib.c
* lib/linux/riscv64-mes-m2/_exit.c,
lib/linux/riscv64-mes-m2/_write.c,
lib/linux/riscv64-mes-m2/crt1.c,
lib/linux/riscv64-mes-m2/syscall.c: New files, adapted for M2-Planet
calling convention from ...
* lib/linux/riscv64-mes-mescc: ...here
* kaem.run: Move fcntl.h up. Include signal.h.
* build-aux/build.sh.in: Also allow kaem build for riscv64.
* lib/riscv64-mes/riscv64.M1: New file. Add set of instruction macros
for RV64. These are all potentially needed by the code generation. I
have made no effort yet to minimize the list of instructions for mes+tcc
compile.
