Fix libfifolog dependency on libz

Consumers should not need to encode fifolog's dependency on libz.
Handle it automatically in src.libnames.mk.

Differential Revision:	https://reviews.freebsd.org/D2278
Reviewed by:	bapt
Sponsored by:	The FreeBSD Foundation

share/mk/src.libnames.mk

@@ -259,6 +259,9 @@ LDADD_sqlite3+=	${LDADD_pthread}
 DPADD_atf_cxx+=	${DPADD_atf_c}
 LDADD_atf_cxx+=	${LDADD_atf_c}
 
+DPADD_fifolog+=	${DPADD_z}
+LDADD_fifolog+=	${LDADD_z}
+
 DPADD_ipf+=	${DPADD_kvm}
 LDADD_ipf+=	${LDADD_kvm}
 

usr.sbin/fifolog/fifolog_reader/Makefile

@@ -6,7 +6,7 @@ CFLAGS+= -I${.CURDIR}/../lib
 
 MAN=
 
-LIBADD=	z fifolog
+LIBADD=	fifolog
 
 regress:
 	./${PROG} /tmp/fifolog.0

usr.sbin/fifolog/fifolog_writer/Makefile

@@ -6,7 +6,7 @@ CFLAGS+= -I${.CURDIR}/../lib
 
 MAN=
 
-LIBADD=	z fifolog
+LIBADD=	fifolog
 
 regress:
 	date | ./${PROG} -z 0 /tmp/fifolog.0