powerpc: Disable -Wbuiltin-requires-header when setjmp is used

[Michael Ellerman]

On Mon, 2018-09-17 at 07:46:21 UTC, Joel Stanley wrote:
> The powerpc kernel uses setjmp which causes a warning when building with
> clang:
> 
>     CC      arch/powerpc/xmon/xmon.o
>   In file included from arch/powerpc/xmon/xmon.c:51:
>   ./arch/powerpc/include/asm/setjmp.h:15:13: error: declaration of
>   built-in function 'setjmp' requires inclusion of the header <setjmp.h>
>         [-Werror,-Wbuiltin-requires-header]
>   extern long setjmp(long *);
>               ^
>   ./arch/powerpc/include/asm/setjmp.h:16:13: error: declaration of
>   built-in function 'longjmp' requires inclusion of the header <setjmp.h>
>         [-Werror,-Wbuiltin-requires-header]
>   extern void longjmp(long *, long);
>               ^
> 
> This *is* the header and we're not using the built-in setjump but
> rather the one in arch/powerpc/kernel/misc.S. As the compiler warning
> does not make sense, it for the files where setjmp is used.
> 
> Signed-off-by: Joel Stanley <joel at jms.id.au>
> Reviewed-by: Nick Desaulniers <ndesaulniers at google.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/aea447141c7e7824b81b49acd1bc78

cheers