Change in libffi behaviour -- large struct args

[DJ Delorie]

Anthony Green <green@moxielogic.com> writes:
>> While this is technically an ABI change, if the "old" ABI never worked,
>> I can't see how this would break anything by changing.
>
> I wouldn't even call this an ABI change.   The new implementation will
> be ABI compatible.  This is really a bug fix.   In fact, some ports
> have always done the right thing.

Right, I was using ABI to mean "the ABI of the target we're composing a
foreign call for", not the call ABI of the libffi library.

If we could not correctly call functions that took large structures, and
now we can, we have changed the target ABI but shouldn't break any
existing software that worked correctly before.

I agree it's worth fixing, we just must be careful we actually *don't*
break any currently-working program.