net/netcat: Workaround LLVM15 build errors

Circumvent LLVM build errors. Permanent fixes will come later.

While at it, assume care and feeding of this port.

MFH:		2023Q2

net/netcat/Makefile

@@ -10,14 +10,14 @@ PATCH_SITES=	GENTOO
 PATCHFILES=	nc-v6-20000918.patch.gz
 PATCH_DIST_STRIP=	-p1
 
-MAINTAINER=	ports@FreeBSD.org
+MAINTAINER=	cy@FreeBSD.org
 COMMENT=	Simple utility which reads and writes data across network connections
 WWW=		http://nc110.sourceforge.net/
 
 USES=		tar:tgz
 NO_WRKSUBDIR=	yes
 
-CFLAGS+=	-D${OPSYS:tu}
+CFLAGS+=	-D${OPSYS:tu} -Wno-int-conversion
 LDFLAGS+=	-static
 
 PORTDOCS=	README