Makefile: Use VPATH to avoid rsync

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

Author: ejona86

Makefile

@@ -42,11 +42,10 @@ mrproper: FORCE clean
 	rm -rf ext
 
 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.dfu $(mcu)=y $(level)=y $(target)=y
+	$(MAKE) VPATH=$(ROOT)/src -C out/$(mcu)/$(level)/$(target) -f $(ROOT)/Rules.mk target.bin target.hex target.dfu $(mcu)=y $(level)=y $(target)=y
 
 HXC_FF_URL := https://www.github.com/keirf/flashfloppy-hxc-file-selector
 HXC_FF_URL := $(HXC_FF_URL)/releases/download

Rules.mk

@@ -73,7 +73,8 @@ build.o: $(OBJS)
 	$(LD) -r -o $@ $^
 
 %/build.o: FORCE
-	$(MAKE) -f $(ROOT)/Rules.mk -C $* build.o
+	+mkdir -p $*
+	$(MAKE) VPATH=$(VPATH)/$* -f $(ROOT)/Rules.mk -C $* build.o
 
 %.ld: $(SRCDIR)/%.ld.S $(SRCDIR)/Makefile
 	@echo CPP $@