Use libelf from base.

Index: cddl/usr.bin/ctfdump/Makefile
--- cddl/usr.bin/ctfdump/Makefile.orig
+++ cddl/usr.bin/ctfdump/Makefile
@@ -17,9 +17,8 @@ CFLAGS+=	-I${OPENSOLARIS_USR_DISTDIR} \
 		-I${.CURDIR}/../../../sys/cddl/compat/opensolaris \
 		-I${.CURDIR}/../../../cddl/compat/opensolaris/include \
 		-I${OPENSOLARIS_USR_DISTDIR}/tools/ctf/common \
-		-I${OPENSOLARIS_SYS_DISTDIR}/uts/common \
-		-I/usr/local/include/elftoolchain
+		-I${OPENSOLARIS_SYS_DISTDIR}/uts/common
 
-LDADD=		-L/usr/local/lib/elftoolchain -lelf -lz
+LDADD=		-lelf -lz
 
 .include <bsd.prog.mk>