Add two debug rules the examine the values of runtime make variables. Based on...

Add two debug rules the examine the values of runtime make variables. Based on patch by Philip Prindeville <philipp@redfish-solutions.com>

SVN-Revision: 23389

rules.mk

@@ -254,4 +254,16 @@ all:
 FORCE: ;
 .PHONY: FORCE
 
+val.%:
+	@$(if $(filter undefined,$(origin $*)),\
+		echo "$* undefined" >&2, \
+		echo '$(subst ','"'"',$($*))' \
+	)
+
+var.%:
+	@$(if $(filter undefined,$(origin $*)),\
+		echo "$* undefined" >&2, \
+		echo "$*='"'$(subst ','"'\"'\"'"',$($*))'"'" \
+	)
+
 endif #__rules_inc