tcp_wrappers: Use default C standard version

Reviewed by:	emaste, arichardson, jhb
Differential Revision: https://reviews.freebsd.org/D43236

contrib/tcp_wrappers/tcpd.c

@@ -44,6 +44,7 @@ static char sccsid[] = "@(#) tcpd.c 1.10 96/02/11 17:01:32";
 int     allow_severity = SEVERITY;	/* run-time adjustable */
 int     deny_severity = LOG_WARNING;	/* ditto */
 
+int
 main(int argc, char **argv)
 {
     struct request_info request;

libexec/tcpd/Makefile

@@ -6,7 +6,6 @@ PACKAGE=	tcpd
 
 PROG=	tcpd
 MAN=	tcpd.8
-CSTD?=	c89
 CFLAGS+=-DREAL_DAEMON_DIR=\"${LIBEXECDIR}\" \
 	-DSEVERITY=LOG_INFO -DRFC931_TIMEOUT=10 \
 	-DHOSTS_DENY=\"/etc/hosts.deny\" -DHOSTS_ALLOW=\"/etc/hosts.allow\" \