[PATCH][ARM]Fix urem/srem of i64 for aeabi target (PR 17881)

[Tim Northover]

>> I read the other patch (devmod-legal) and seems OK. Why doesn’t it work?
>
> It does. But people were uncomfrotable with the notion of having
> ABI-specific knowledge in generic code. But as I said, it's already
> ABI-specific (GNU's), so I don't agree with that argument. However, they
> were all against me, so I yielded. ;)

For me the difference is that GNU's ABI has at least some claim to
being cross-platform. I actually think the ARM one is superior, but
it's not going to be useful to anyone not implementing AEABI so
keeping it out of generic code is the best solution (IMO).

Cheers.

Tim.