Makefile: Replace rsync with individual mkdir in pattern rule

Also add + to mkdir lines to fix --dry-run.

Makefile

@@ -30,8 +30,7 @@ clean: FORCE
 	rm -rf out
 
 out: FORCE
-	mkdir -p out/$(mcu)/$(level)/$(target)
-	rsync -a --include="*/" --exclude="*" src/ out/$(mcu)/$(level)/$(target)
+	+mkdir -p out/$(mcu)/$(level)/$(target)
 
 target: FORCE out
 	$(MAKE) -C out/$(mcu)/$(level)/$(target) -f $(ROOT)/Rules.mk target.bin target.hex target.upd $(mcu)=y $(level)=y $(target)=y

Rules.mk

@@ -64,6 +64,7 @@ build.o: $(OBJS)
 	$(LD) -r -o $@ $^
 
 %/build.o: FORCE
+	+mkdir -p $*
 	$(MAKE) -f $(ROOT)/Rules.mk -C $* build.o
 
 %.ld: $(SRCDIR)/%.ld.S $(SRCDIR)/Makefile