x86_64: build: Cater for M2-Planet.
* build-aux/cflags.sh: Set cc_cpu.
* build-aux/config.sh.in (cc_cpu): Export.
* build-aux/export.make (cc_cpu): Likewise.
* kaem.arm (cc_cpu): New variable.
* kaem.x86 (cc_cpu): New variable.
* kaem.run (cc_cpu): New variable. Define __<cc_cpu>__.
* scaffold/argv.kaem (cc_cpu): Likewise. Define __linux__
* scaffold/global-array.kaem (cc_cpu): Likewise.
* scaffold/hello.kaem (cc_cpu): Likewise.
* scaffold/local-array.kaem (cc_cpu): Likewise.
* scaffold/local-static-array.kaem (cc_cpu): Likewise.
* scaffold/main.kaem (cc_cpu): Likewise.
* scaffold/read.kaem (cc_cpu): Likewise.
* kaem.x86_64: New file.
lib/m2/x86_64/ELF-x86_64.hex2,
lib/m2/x86_64/x86_64_defs.M1: New files, imported from M2Libc.
lib/linux/x86_64-mes-m2/_exit.c,
lib/linux/x86_64-mes-m2/_write.c,
lib/linux/x86_64-mes-m2/crt1.M1,
lib/linux/x86_64-mes-m2/crt1.c,
lib/linux/x86_64-mes-m2/syscall.c: New files, adapted for M2-Planet
calling convention from ...
* lib/linux/x86_64-mes-mescc: ... here.
* build-aux/build.sh.in: Also allow kaem build for x86_64.
* include/mes/lib-mini.h[__M2__]: Define as sizeof (void*).
* include/mes/mes.h[__M2__](M2_CELL_SIZE): Define as sizeof (struct scm).
* lib/x86_64-mes/x86_64.M1 (add____$i8,%rbp, mov____%rdi,%rbp): New
defines.
* src/posix.c (TIME_UNITS_PER_SECOND): Cater for 64bit M2-Planet.
c8294803cd