databases/rrdtool: fix build with lld 17

Some symbols in the linker version script librrd.sym are undefined when
the CACHE option is off. Suppress errors with lld >= 17 due to these
undefined symbols.

PR:		273753
MFH:		2024Q1

databases/rrdtool/Makefile

@@ -1,6 +1,6 @@
 PORTNAME=	rrdtool
 DISTVERSION=	1.8.0
-PORTREVISION=	2
+PORTREVISION=	3
 CATEGORIES=	databases graphics
 MASTER_SITES=	https://github.com/oetiker/rrdtool-1.x/releases/download/v${DISTVERSION}/
 
@@ -22,6 +22,10 @@ CONFIGURE_ARGS=	--disable-tcl
 CONFIGURE_ENV=	RRDDOCDIR=${DOCSDIR:Q}
 INSTALL_TARGET=	install-strip
 CPPFLAGS+=	-I${LOCALBASE}/include -I${LOCALBASE}/include/freetype2
+# Some symbols in the linker version script librrd.sym are undefined when the
+# CACHE option is off. Suppress errors with lld >= 17 due to these undefined
+# symbols.
+LDFLAGS+=	-Wl,--undefined-version
 CONFLICTS=	rrdtool12
 PORTDOCS=	*
 PORTEXAMPLES=	cgi-demo.cgi