* build-aux/build-guile.sh: Add ARM backend.
* lib/arm-mes/arm.M1: New file.
* module/mescc/armv4/as.scm: New file.
* module/mescc/armv4/info.scm: New file.
* module/mescc/mescc.scm: Use it.
* module/mescc/M1.scm (info->M1): Support ARM symbolic instructions,
including little endian instructions. Align functions.