Allow to disable build of as backends for obsolete architectures.

diff --git a/as/Makefile b/as/Makefile
index a4b016e..9e8bcc3 100644
--- a/as/Makefile
+++ b/as/Makefile
@@ -1,3 +1,4 @@
+BUILD_OBSOLETE_ARCH = yes
 export USE_APPLE_PB_SUPPORT = all
 
 ifneq "" "$(SDKROOT)"
@@ -20,28 +21,36 @@ SRCROOT = .
 SYMROOT = .
 OBJROOT = .
 SYM_DIRS = $(SYMROOT)/driver_dir \
-	   $(SYMROOT)/a68_dir \
-	   $(SYMROOT)/a88_dir \
 	   $(SYMROOT)/a386_dir \
  	   $(SYMROOT)/ax86_64_dir \
 	   $(SYMROOT)/appc_dir \
 	   $(SYMROOT)/appc64_dir \
+	   $(SYMROOT)/aarm_dir 
+
+ifeq "yes" "$(BUILD_OBSOLETE_ARCH)"
+SYM_DIRS += \
+	   $(SYMROOT)/a68_dir \
+	   $(SYMROOT)/a88_dir \
 	   $(SYMROOT)/a860_dir \
 	   $(SYMROOT)/ahppa_dir \
-	   $(SYMROOT)/asparc_dir \
-	   $(SYMROOT)/aarm_dir 
+	   $(SYMROOT)/asparc_dir
+endif
 
 OFILE_DIRS = $(OBJROOT)/driver_dir \
-	     $(OBJROOT)/a68_dir \
-	     $(OBJROOT)/a88_dir \
 	     $(OBJROOT)/a386_dir \
  	     $(OBJROOT)/ax86_64_dir \
 	     $(OBJROOT)/appc_dir \
 	     $(OBJROOT)/appc64_dir \
+	     $(OBJROOT)/aarm_dir
+
+ifeq "yes" "$(BUILD_OBSOLETE_ARCH)"
+OFILE_DIRS += \
+	     $(OBJROOT)/a68_dir \
+	     $(OBJROOT)/a88_dir \
 	     $(OBJROOT)/a860_dir \
 	     $(OBJROOT)/ahppa_dir \
-	     $(OBJROOT)/asparc_dir \
-	     $(OBJROOT)/aarm_dir
+	     $(OBJROOT)/asparc_dir
+endif
 
 BINDIR = /bin
 USRBINDIR = /usr/bin
@@ -88,9 +97,13 @@ OBJS_hppa = $(CFILES_hppa:.c=.o)
 OBJS_sparc = $(CFILES_sparc:.c=.o)
 OBJS_arm = $(CFILES_arm:.c=.o)
 
-all:	$(OFILE_DIRS) $(SYM_DIRS) driver_build a68_build a88_build a386_build \
-	ax86_64_build a860_build appc_build appc64_build ahppa_build \
-	aarm_build asparc_build
+all:	$(OFILE_DIRS) $(SYM_DIRS) driver_build a386_build \
+	ax86_64_build appc_build appc64_build aarm_build
+
+ifeq "yes" "$(BUILD_OBSOLETE_ARCH)"
+all: 	a68_build a88_build a860_build ahppa_build asparc_build
+endif
+
 
 all_test:	a68_test a88_test a860_test a386_test appc_test ahppa_test
 
@@ -406,15 +419,18 @@ install: all
 	$(MKDIRS) $(DSTROOT)$(LOCLIBDIR)/ppc64
 	install -c -s -m 555 $(SYMROOT)/appc64_dir/as \
 		$(DSTROOT)$(LOCLIBDIR)/ppc64/as
+ifeq "yes" "$(BUILD_OBSOLETE_ARCH)"
 	$(MKDIRS) $(DSTROOT)$(LOCLIBDIR)/m68k
 	install -c -s -m 555 $(SYMROOT)/a68_dir/as \
 		$(DSTROOT)$(LOCLIBDIR)/m68k/as
 	$(MKDIRS) $(DSTROOT)$(LOCLIBDIR)/sparc 
 	install -c -s -m 555 $(SYMROOT)/asparc_dir/as \
 		$(DSTROOT)$(LOCLIBDIR)/sparc/as
+endif
 	$(MKDIRS) $(DSTROOT)$(LIBDIR)/arm
 	install -c -s -m 555 $(SYMROOT)/aarm_dir/as \
 		$(DSTROOT)$(LIBDIR)/arm/as
+ifeq "yes" "$(BUILD_OBSOLETE_ARCH)"
 	$(MKDIRS) $(DSTROOT)$(LOCLIBDIR)/m88k
 	install -c -s -m 555 $(SYMROOT)/a88_dir/as \
 		$(DSTROOT)$(LOCLIBDIR)/m88k/as
@@ -424,6 +440,7 @@ install: all
 	$(MKDIRS) $(DSTROOT)$(LOCLIBDIR)/i860
 	install -s -m 555 $(SYMROOT)/a860_dir/as \
 		$(DSTROOT)$(LOCLIBDIR)/i860/as
+endif
 
 $(OFILE_DIRS) $(SYM_DIRS):
 	$(MKDIRS) $@