Add missing hidden_def (__sigsetjmp).
This patch adds the missing hidden_def (__sigsetjmp) on various
architectures that were failing to build (as noted in
<https://sourceware.org/ml/libc-alpha/2016-11/msg01124.html>).
Tested (compilation only) with build-many-glibcs.py.
* sysdeps/alpha/setjmp.S (__sigsetjmp): Use hidden_def.
* sysdeps/hppa/setjmp.S (__sigsetjmp): Likewise.
* sysdeps/mips/mips64/setjmp.S (__sigsetjmp): Likewise.
* sysdeps/mips/setjmp.S (__sigsetjmp): Likewise.
* sysdeps/sh/sh3/setjmp.S (__sigsetjmp): Likewise.
* sysdeps/sh/sh4/setjmp.S (__sigsetjmp): Likewise.
* sysdeps/sparc/sparc32/setjmp.S (__sigsetjmp): Likewise.
* sysdeps/tile/setjmp.S (__sigsetjmp): Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/setjmp.S (__sigsetjmp):
Likewise.