Questions about --with-alpha and --with-armeb configure flags

Hello, I've several questions about the --with-alpha and --with-armeb build-time flags. 1) are --with-alpha and --with-armeb intended to be enabled only on these architectures on could they also be enabled on any other one? If I understand correctly it's only adding arch detection and syscall tables to ausyscall. Why are these syscall table conditional? 2) Is --with-armeb meant for ARMEB (aka ARM big-endian) or is it meant for ARM with embedded ABI? The help message of the configure says the later but it seems to be badly named. If somebody could enlighten me, Kind regards Laurent Bigonville