[patch] declare __clear_cache

[Tim Northover]

Hi Rafael,

> in the gnu modes (-std=gnu++98, -std=gnu++11), but not in the strict
> modes (-std=c++11).
>
> It is easy to just build with -std=gnu++11, but since this small patch
> is all that is needed to build with -std=c++11, it is probably a good
> thing, no?

Ah, that explains it. Unfortunately the definition you're proposing
will make clang refuse to compile the file for 32-bit ARM.

It thinks the function has some variadic type (in violation of the
documentation, but in line with some bizarre historical use according
to some Clang comments).

> I will update the patch to correct the builtin definition in clang too.

Thanks for the offer; I've already corrected it though.

Tim.