make: set MACHINE_ARCH variable

Also, modify sys.mk so we continue to build with -O

commands/make/Makefile

@@ -21,7 +21,8 @@ MACHINE=${ARCH}
 MACHINE_ARCH=${ARCH}
 CPPFLAGS+= -DTARGET_MACHINE=\"${MACHINE}\" \
 	-DTARGET_MACHINE_ARCH=\"${MACHINE_ARCH}\" \
-	-DMAKE_MACHINE=\"${MACHINE}\"
+	-DMAKE_MACHINE=\"${MACHINE}\" \
+	-DMAKE_MACHINE_ARCH=\"${MACHINE_ARCH}\"
 
 
  .PATH:	${.CURDIR}/lst.lib

lib/nbsd_libm/Makefile

@@ -13,10 +13,6 @@
 #
 #
 
-.if ${MACHINE_ARCH} == "unknown"
-MACHINE_ARCH:= ${MACHINE}
-.endif
-
 #
 # There are two options in making libm at fdlibm compile time:
 # 	_IEEE_LIBM 	--- IEEE libm; smaller, and somewhat faster

share/mk/sys.mk

@@ -36,7 +36,9 @@ CC?=		cc
     ${MACHINE_ARCH} == "powerpc" || \
     ${MACHINE_ARCH} == "sparc" || \
     ${MACHINE_ARCH} == "sparc64"
-DBG?=	-O2
+#DBG?=	-O2
+#MINIX: use -O for now
+DBG?=	-O
 .elif ${MACHINE_ARCH} == "sh3el" || ${MACHINE_ARCH} == "sh3eb"
 # -O2 is too -falign-* zealous for low-memory sh3 machines
 DBG?=	-Os -freorder-blocks