Move mac.conf to lib/libc/posix1e/

This leverages CONFS to handle the install of the config file.

Approved by:	re (blanket, pkgbase), will (mentor)
Differential Revision:	https://reviews.freebsd.org/D17162

etc/Makefile

@@ -18,7 +18,6 @@ BIN1=	\
 	hosts.allow \
 	libalias.conf \
 	login.access \
-	mac.conf \
 	phones \
 	rc.bsdextended \
 	rc.firewall \

lib/libc/posix1e/Makefile.inc

@@ -8,6 +8,7 @@ CFLAGS+=-D_ACL_PRIVATE
 subr_acl_nfs4.c: ${SRCTOP}/sys/kern/subr_acl_nfs4.c
 	cat ${.ALLSRC} > ${.TARGET}
 
+CONFS+=	posix1e/mac.conf
 SRCS+=	acl_branding.c			\
 	acl_calc_mask.c			\
 	acl_copy.c			\