Hide internal __setrlimit function [BZ #18822]

Hide internal __setrlimit function [BZ #18822]

Hide internal __setrlimit function to allow direct access within libc.so
and libc.a without using GOT nor PLT.

	[BZ #18822]
	* include/sys/resource.h (__setrlimit): Add libc_hidden_proto.
	* resource/setrlimit.c (__setrlimit): Add libc_hidden_def.
	* sysdeps/mach/hurd/setrlimit.c (__setrlimit): Likewise.
	* sysdeps/unix/sysv/linux/setrlimit.c (__setrlimit): Likewise.
	* sysdeps/unix/sysv/linux/setrlimit64.c (__GI___setrlimit): New.