o Ensure va_list is declared by including stdarg.h.

o Also move printf.h to go after it since it does require declaration
  of va_list.

This fixes build with latest RISC-V GNU Toolchain with GCC 8.1

Sponsored by:	DARPA, AFRL

contrib/blacklist/bin/blacklistctl.c

@@ -35,6 +35,7 @@
 #include <sys/cdefs.h>
 __RCSID("$NetBSD: blacklistctl.c,v 1.21 2016/11/02 03:15:07 jnemeth Exp $");
 
+#include <stdarg.h>
 #include <stdio.h>
 #include <time.h>
 #ifdef HAVE_LIBUTIL_H

lib/libpjdlog/pjdlog.c

@@ -43,8 +43,8 @@ __FBSDID("$FreeBSD$");
 #include <errno.h>
 #include <libutil.h>
 #include <limits.h>
-#include <printf.h>
 #include <stdarg.h>
+#include <printf.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>

sbin/hastd/pjdlog.c

@@ -41,8 +41,8 @@ __FBSDID("$FreeBSD$");
 #include <assert.h>
 #include <errno.h>
 #include <libutil.h>
-#include <printf.h>
 #include <stdarg.h>
+#include <printf.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>