Use a non-tricky approach for building and installing zfsboot sharing

the Makefile with boot1.

Submitted by:	ru

sys/boot/sparc64/boot1/Makefile

@@ -5,7 +5,7 @@ INTERNALPROG=
 NO_MAN=
 FILES?=	boot1
 SRCS=	_start.s boot1.c
-CLEANFILES+=boot1 boot1.aout
+CLEANFILES=${FILES} boot1.aout
 
 BOOTBLOCKBASE= 0x4000
 
@@ -14,7 +14,7 @@ LDFLAGS=-Ttext ${BOOTBLOCKBASE} -Wl,-N
 
 # Construct boot1. sunlabel expects it to contain zeroed-out space for the
 # label, and to be of the correct size.
-boot1: boot1.aout
+${FILES}: boot1.aout
 	@set -- `ls -l boot1.aout`; x=$$((7680-$$5)); \
 	    echo "$$x bytes available"; test $$x -ge 0
 	dd if=/dev/zero of=${.TARGET} bs=512 count=16

sys/boot/sparc64/zfsboot/Makefile

@@ -5,9 +5,5 @@
 PROGNAME=	zfsboot
 CFLAGS+=	-DZFSBOOT
 FILES=		zfsboot
-CLEANFILES+=	zfsboot
-
-zfsboot: boot1
-	ln -s ${.ALLSRC} ${.TARGET}
 
 .include "${.CURDIR}/../boot1/Makefile"