Add VDSO support to sparc.

	* sysdeps/unix/sysv/linux/sparc/init-first.c: New file.
	* sysdeps/unix/sysv/linux/sparc/libc-vdso.h: New file.
	* sysdeps/unix/sysv/linux/sparc/Makefile: Add dl-vdso to
	sysdep_routines in subdir elf.
	* sysdeps/unix/sysv/linux/sparc/Versions: Add GLIBC_PRIVATE
	version for __vdso_clock_gettime.
	* sysdeps/unix/sysv/linux/sparc/sysdep.h (INTERNAL_VSYSCALL_CALL):
	Define.
	(HAVE_CLOCK_GETTIME_VSYSCALL): Define.
	(HAVE_GETTIMEOFDAY_VSYSCALL): Define.