parisc: sigaltstack doesn't round ss.ss_sp as required

On 24-Nov-12, at 10:05 AM, John David Anglin wrote:

> In trying to build the debian libsigsegv2 package, I found that sigaltstack
> doesn't round ss.ss_sp. The tests intentionally pass an unaligned pointer.
> This results in the two stack overflow tests failing.

The attached patch fixes this issue.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>