* sysdeps/powerpc/elf/libc-start.c: Make AUXVEC diddling code

* sysdeps/powerpc/elf/libc-start.c: Make AUXVEC diddling code

	conditional on [HAVE_AUX_VECTOR].

	* mach/mach/mach_traps.h (thread_switch, __thread_switch): Use
	mach_msg_timeout_t as type of final argument.

	* hurd/privports.c (__get_privileged_ports):
	Change host_priv_t to mach_port_t in argument type.
	* hurd/hurd.h (get_privileged_ports, __get_privileged_ports):
	Update decls.

	* sysdeps/mach/hurd/i386/bits/sigcontext.h: Protect from
	multiple inclusion.  Inhibit #error under [_SYS_UCONTEXT_H].
	* sysdeps/mach/hurd/alpha/bits/sigcontext.h: Likewise.
	* sysdeps/mach/hurd/hppa/bits/sigcontext.h: Likewise.
	* sysdeps/mach/hurd/mips/bits/sigcontext.h: Likewise.
	* sysdeps/mach/hurd/powerpc/bits/sigcontext.h: Likewise.