[sparc64/base-gcc] Fix build of security/opendnssec

[Kurt Mosiejczuk]

opendnssec uses C99 constructs.

This fixes the build on sparc64

ok?

(cc maintainer)

--Kurt

Index: Makefile
===================================================================
RCS file: /cvs/ports/security/opendnssec/Makefile,v
retrieving revision 1.24
diff -u -p -r1.24 Makefile
--- Makefile    27 Feb 2021 20:50:33 -0000      1.24
+++ Makefile    16 May 2021 03:45:40 -0000
@@ -97,4 +97,9 @@ post-install:
        ${INSTALL_DATA} 
${WRKSRC}/enforcer/utils/1.4-2.0_db_convert/mysql_convert.sql \
                ${PREFIX}/share/opendnssec/migration/migrate-mysql.sql
 
+.include <bsd.port.arch.mk>
+.if !${PROPERTIES:Mclang}
+CFLAGS +=      -std=gnu99
+.endif
+
 .include <bsd.port.mk>