[PATCH] AArch64/ILP32: fix wrong sign extension in setgroups

[Roland McGrath]

> Roland McGrath <roland@hack.frob.com> writes:
> 
> > But I don't quite understand why the new setgroups.c is required.
> 
> It's required to avoid a warning about casting different sized types
> (pointer vs. __syscall_slong_t).  I'll add a comment.

Perhaps just add the cast to the linux/setgroups.c implementation?
It's pretty much universal that INLINE_SYSCALL does not know anything
useful about the types of the arguments and casts them to a type like
__syscall_slong_t.  We could make this a documented requirement for
using those macros.