diff --git a/astro/openuniverse/Makefile b/astro/openuniverse/Makefile
index 9d08ff83dd1f..c3bb2a42976f 100644
--- a/astro/openuniverse/Makefile
+++ b/astro/openuniverse/Makefile
@@ -1,23 +1,29 @@
 PORTNAME=	openuniverse
 DISTVERSION=	1.0beta3
 PORTREVISION=	16
 CATEGORIES=	astro
 MASTER_SITES=	SF/${PORTNAME}/${PORTNAME}/${DISTVERSION}
 
 MAINTAINER=	mew14930xvi@inbox.lv
 COMMENT=	OpenGL Solar System simulator for X Window System
 WWW=		https://openuniverse.sourceforge.net/
 
 LICENSE=	GPLv2
 LICENSE_FILE=	${WRKSRC}/COPYING
 
 USES=		gl gmake jpeg localbase xorg
 USE_CXXSTD=	c++98
 USE_GL=		gl glu glut
 USE_XORG=	ice sm x11 xext xi xmu xorgproto
 
 GNU_CONFIGURE=	yes
 
+.include <bsd.port.pre.mk>
+
+.if ${OPSYS}_${OSREL:R} == FreeBSD_13
+LIBS+=		-lcompat
+.else
 LIBS+=		-lutil
+.endif
 
-.include <bsd.port.mk>
+.include <bsd.port.post.mk>