PPC32: check the binutils version and make sure it is new enough.

arch/ppc/Makefile

@@ -116,3 +116,24 @@ archclean:
 	@$(MAKEBOOT) clean
 
 archmrproper:
+
+prepare: checkbin
+
+ifdef CONFIG_6xx
+# Ensure this is binutils 2.12.1 (or 2.12.90.0.7) or later
+NEW_AS	:= $(shell echo dssall | $(AS) -o /dev/null >/dev/null 2>&1 ; echo $$?)
+GOODVER	:= 2.12.1
+else
+NEW_AS	:= 0
+endif
+
+ifneq ($(NEW_AS),0)
+checkbin:
+	@echo -n '*** ${VERSION}.${PATCHLEVEL} kernels no longer build'
+	@echo 'correctly with old versions of binutils.'
+	@echo '*** Please upgrade your binutils to ${GOODVER} or newer'
+	@false
+else
+checkbin:
+	@true
+endif