Index: head/devel/dwarves/Makefile
===================================================================
--- head/devel/dwarves/Makefile	(revision 433956)
+++ head/devel/dwarves/Makefile	(revision 433957)
@@ -1,42 +1,48 @@
 # Created by: Conrad Meyer <cem@FreeBSD.org>
 # $FreeBSD$
 
 PORTNAME=	dwarves
 PORTVERSION=	1.10.20160713
 PORTREVISION=	1
 CATEGORIES=	devel
 #MASTER_SITES=	https://fedorapeople.org/~acme/dwarves/
 MASTER_SITES=	http://repo.or.cz/dwarves.git/snapshot/
 DISTFILES=	b52386d041fac2dc6decf3a9e8e85385784a2de9.tar.gz
 # git: http://repo.or.cz/dwarves.git
 # ML: http://news.gmane.org/gmane.comp.debugging.dwarves
 
 MAINTAINER=	cem@FreeBSD.org
 COMMENT=	Debugging Information Manipulation Tools
 
 LICENSE=	GPLv2
 LICENSE_FILE_GPLv2=	${WRKSRC}/COPYING
 
 BROKEN=		does not build (/usr/local/include/libelf.h:308:8: error: unknown type name 'Elf32_Chdr')
 
 LIB_DEPENDS=	libargp.so:devel/argp-standalone \
 		libdw.so:devel/elfutils
 PATCH_DEPENDS=	gnulib>=0:devel/gnulib
 
 WRKSRC=		${WRKDIR}/dwarves-b52386d
 
 USES=		cmake:outsource localbase shebangfix tar:bzip2
 USE_LDCONFIG=	yes
 
 SHEBANG_FILES=	ostra/ostra-cg
 
 post-patch:
 	@${CP} -a \
 	    ${LOCALBASE}/share/gnulib/lib/gettext.h \
 	    ${LOCALBASE}/share/gnulib/lib/obstack.c \
 	    ${LOCALBASE}/share/gnulib/lib/obstack.h \
 	    ${WRKSRC}/
 	@${REINPLACE_CMD} -e 's|_GL_ATTRIBUTE_PURE|__attribute__((__pure__))|g' \
 	    ${WRKSRC}/obstack.h ${WRKSRC}/obstack.c
 
-.include <bsd.port.mk>
+.include <bsd.port.pre.mk>
+
+.if ${OSVERSION} < 1200000
+IGNORE=		requires FreeBSD 12.0 (ElfNN_Chdr)
+.endif
+
+.include <bsd.port.post.mk>