Further refinement to bmake bootstrapping

Include PROGNAME and DESTDIR in ${MMAKE} so that it doesn't need to be
passed to each make invocation.

Suggested by:	hrs
Reviewed by:	hrs
Approved by:	re (gjb)

Makefile

@@ -341,7 +341,7 @@ MMAKEENV=	MAKEOBJDIRPREFIX=${MYMAKE:H} \
 MMAKE=		${MMAKEENV} ${MAKE} \
 		-D_UPGRADING \
 		-DNOMAN -DNO_MAN -DNOSHARED -DNO_SHARED \
-		-DNO_CPU_CFLAGS -DNO_WERROR
+		-DNO_CPU_CFLAGS -DNO_WERROR DESTDIR= PROGNAME=${MYMAKE:T}
 
 make bmake: .PHONY
 	@echo
@@ -349,10 +349,10 @@ make bmake: .PHONY
 	@echo ">>> Building an up-to-date make(1)"
 	@echo "--------------------------------------------------------------"
 	${_+_}@cd ${.CURDIR}/usr.bin/${.TARGET}; \
-		${MMAKE} obj DESTDIR= && \
-		${MMAKE} depend DESTDIR= && \
-		${MMAKE} all DESTDIR= PROGNAME=${MYMAKE:T} && \
-		${MMAKE} install DESTDIR=${MYMAKE:H} BINDIR= PROGNAME=${MYMAKE:T}
+		${MMAKE} obj && \
+		${MMAKE} depend && \
+		${MMAKE} all && \
+		${MMAKE} install DESTDIR=${MYMAKE:H} BINDIR=
 
 tinderbox toolchains kernel-toolchains: upgrade_checks