[PATCH] hppa: Fix stack alignment passed to clone

[Florian Weimer]

* John David Anglin:

> The other alternative is to generate an error when passed a
> misaligned stack argument.  I looked at the opengroup spec but it
> didn't clarify the situations where arguments are invalid.

I think an unaligned stack triggers undefined behavior, so a crash
would be acceptable in this context.  We could maybe add an assert to
the thread creation (although that will cause backwards compatibility
concerns on i386 due to the silent ABI change for SSE2).