Upgrade unbound library

These files were pulled from the 1.6.3 release tarball.

This new version builds against OpenSSL version 1.1 which will be
the default in the new Debian Stable which is due to be released
RealSoonNow (tm).

external/unbound/smallapp/unbound-host.c

@@ -72,7 +72,7 @@ static int verb = 0;
 
 /** Give unbound-host usage, and exit (1). */
 static void
-usage()
+usage(void)
 {
 	printf("Usage:	unbound-host [-vdhr46] [-c class] [-t type] hostname\n");
 	printf("                     [-y key] [-f keyfile] [-F namedkeyfile]\n");
@@ -91,7 +91,7 @@ usage()
 	printf("    -F keyfile		read named.conf-style trust anchors.\n");
 	printf("    -C config		use the specified unbound.conf (none read by default)\n");
 	printf("    -r			read forwarder information from /etc/resolv.conf\n");
-	printf("      			breaks validation if the fwder does not do DNSSEC.\n");
+	printf("      			breaks validation if the forwarder does not do DNSSEC.\n");
 	printf("    -v			be more verbose, shows nodata and security.\n");
 	printf("    -d			debug, traces the action, -d -d shows more.\n");
 	printf("    -4			use ipv4 network, avoid ipv6.\n");