RPi 3 is ARMv8; looks like it's not exactly backwards compatible (e.g. no coprocessors).
RPi 2 is Cortex-A7 (ARMv7-A&R); very close to DIGIC 6 (Cortex R4). Could be used to understand how to write self-modifying code (the current issue).
RPi 1 is ARMv6; not very interesting for us.
DIGIC 2 to 5 appears to use ARMv5 (ARM946E-S), with some extensions borrowed from newer versions (e.g. WFI, see the arm946eos definition from QEMU).
Didn't try to compile ML from another ARM machine. Could be useful for debugging or optimizing some code sequences (low-level stuff), but other than that, I'm not sure what advantages it would bring over a x86 machine.
Maybe try compiling a simple module with regular gcc?