Use new backup feature of install(1).

libexec/rtld-elf/Makefile

@@ -7,7 +7,7 @@ SRCS=		rtld_start.S rtld.c lockdflt.c map_object.c malloc.c \
 MAN=		rtld.1
 CFLAGS+=	-Wall -DFREEBSD_ELF -I${.CURDIR}/${MACHINE_ARCH} -I${.CURDIR}
 LDFLAGS+=	-nostdlib -e .rtld_start
-INSTALLFLAGS+=	-fschg -C
+INSTALLFLAGS=	-fschg -C -b
 MLINKS=		rtld.1 ld-elf.so.1.1
 
 .if exists(${.CURDIR}/${MACHINE_ARCH}/Makefile.inc)
@@ -42,16 +42,3 @@ dyn_hack.so:
 .PATH: ${.CURDIR}/${MACHINE_ARCH}
 
 .include <bsd.prog.mk>
-
-# Keep the previous version of the dynamic linker for recovery
-# purposes.  This must come after the include of <bsd.prog.mk> so that
-# BINDIR is set for the exists(...) constructs.
-beforeinstall:
-.if exists(${DESTDIR}${BINDIR}/${PROG})
-	-chflags noschg ${DESTDIR}${BINDIR}/${PROG}
-.if exists(${DESTDIR}${BINDIR}/${PROG}.old)
-	-chflags noschg ${DESTDIR}${BINDIR}/${PROG}.old
-.endif
-	${INSTALL} -C -p ${DESTDIR}${BINDIR}/${PROG} \
-	    ${DESTDIR}${BINDIR}/${PROG}.old
-.endif

sbin/init/Makefile

@@ -5,15 +5,9 @@ PROG=	init
 MAN=	init.8
 MLINKS=	init.8 securelevel.8
 BINMODE=500
-INSTALLFLAGS=-fschg
+INSTALLFLAGS=-fschg -b -B.bak
 CFLAGS+=-DDEBUGSHELL -DSECURE -DLOGIN_CAP -DCOMPAT_SYSV_INIT
 DPADD=	${LIBUTIL} ${LIBCRYPT}
 LDADD=	-lutil -lcrypt
 
-beforeinstall:
-.if exists(${DESTDIR}${BINDIR}/${PROG})
-	-chflags noschg ${DESTDIR}${BINDIR}/${PROG}
-	mv ${DESTDIR}${BINDIR}/${PROG} ${DESTDIR}${BINDIR}/${PROG}.bak
-.endif
-
 .include <bsd.prog.mk>