Older zfs boot blocks don't support symlinks. install the link to

zfsloader as a hard link. While newer ones do, the whole point of the
link was to transition to the new world order smoothly. A hard link is
less flexible, but it works and will result in fewer bumps. Adjust
UPDATING entry to match.

UPDATING

@@ -34,9 +34,10 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 12.x IS SLOW:
 20180720:
 	zfsloader's functionality has now been folded into loader.
 	zfsloader is no longer necesasary once you've updated your
-	boot blocks. For a transition period, there will be a symlink
-	in place from zfsloader to loader to allow a smooth transition
-	until the boot blocks can be updated.
+	boot blocks. For a transition period, we will install a
+	hardlink for zfsloader to loader to allow a smooth transition
+	until the boot blocks can be updated (hard link because old
+	zfs boot blocks don't understand symlinks).
 
 20180719:
 	New uid:gid added, ntpd:ntpd (123:123).  Be sure to run mergemaster

stand/i386/loader/Makefile

@@ -65,7 +65,7 @@ ${LOADER}.bin: ${LOADER}.sym
 	strip -R .comment -R .note -o ${.TARGET} ${.ALLSRC}
 
 .if ${MK_ZFS} == "yes"
-SYMLINKS=	${BINDIR}/${LOADER} ${BINDIR}/zfs${LOADER}
+LINKS=		${BINDIR}/${LOADER} ${BINDIR}/zfs${LOADER}
 .endif
 FILES+=	${LOADER}
 # XXX INSTALLFLAGS_loader= -b

stand/sparc64/loader/Makefile

@@ -43,7 +43,7 @@ HELP_FILES=	${.CURDIR}/help.sparc64
 LDFLAGS+=	-static
 
 .if ${MK_ZFS} == "yes"
-SYMLINKS=	${BINDIR}/loader ${BINDIR}/zfsloader
+LINKS=		${BINDIR}/loader ${BINDIR}/zfsloader
 .endif
 
 # Open Firmware standalone support library