[PATCH] Fix __libc_signal_block_all on sparc64

[Florian Weimer]

* Adhemerval Zanella:

> Where SIGALL_SET is defined as:
>
>   ((__sigset_t) { .__val = {[0 ...  _SIGSET_NWORDS-1 ] =  -1 } })

Shouldn't this refer to a global constant data object?  Then we wouldn't
have to emit many local copies of the same object and then copy it onto
the stack.

(GCC cannot know that the system call will not modify the object.)

Thanks,
Florian