build: eliminate "Nothing to be done for `all'" message

Make.rules

@@ -238,7 +238,11 @@ endif
 %/: FORCE
 	$(Q)$(MAKE) -f Make.rules build=$(build-dir) $(MAKECMDGOALS)
 
-compile install:: $(targets)
+compile: $(targets)
+	@:
+
+install:: $(targets) FORCE
+	@:
 
 clean: $(filter %/,$(targets))
 ifeq ($(toplevelrun),yes)