umesimd: arm compatibility
add arm compatibilty: architecture-dependent flag selection, more build flags, some "minor" bugfixes checked on arm with all files checked on intel: 3 files as lab15/16 are still down
add arm compatibilty: architecture-dependent flag selection, more build flags, some "minor" bugfixes checked on arm with all files checked on intel: 3 files as lab15/16 are still down