Follow-up to 7e40a92732c3035003ae779022e5beaf6562375f.
* lib/arm-mes-mescc/setjmp.c (longjmp): Disable.
* lib/linux/arm-mes-mescc/mini.c (_exit): Use ldr.
(_write): Use ldr.
* lib/linux/arm-mes-mescc/syscall.c (__sys_call): Use ldr.
(__sys_call1): Use ldr.
(__sys_call2): Use ldr.
(__sys_call3): Use ldr.
(__sys_call4): Use ldr.
* include/linux/arm/syscall.h: New file.
* lib/arm-mes/arm.M1: New file.
* lib/arm-mes/elf-0footer.hex2: New file.
* lib/arm-mes/elf32-0header.hex2: New file.
* lib/arm-mes/elf32-body-exit-42.hex2: New file.
* lib/arm-mes/elf32-footer-single-main.hex2: New file.
* lib/arm-mes/elf32-header.hex2: New file.
* lib/arm-mes-mescc/exit-42.c: New file.
* lib/arm-mes-mescc/setjmp.c: New file.
* module/mescc/armv4/as.scm: New file.
* module/mescc/armv4/info.scm: New file.
* module/mescc/M1.scm (hex2:offset2): New procedure.
* module/mescc/mescc.scm: Include (mescc armv4 info).
(hex2:offset3): New procedure.
(info->M1): Use them.
* build-aux/build-guile.sh: Compile them.