[Scripts]: rename caravel_out to caravel + copy caravel.gds to caravel.old.gds before generating GDS
diff --git a/Makefile b/Makefile
index 4513822..525b3f8 100644
--- a/Makefile
+++ b/Makefile
@@ -21,6 +21,7 @@
 	@echo "###############################################"
 	@echo "Generating Caravel GDS (sources are in the 'gds' directory)"
 	@sleep 1
+	@cp gds/caravel.gds gds/caravel.old.gds && echo "Copying old Caravel to gds/caravel.old.gds" || true
 	@cd gds && MAGTYPE=mag magic -rcfile ${PDK_ROOT}/sky130A/libs.tech/magic/current/sky130A.magicrc -noc -dnull gen_caravel.tcl < /dev/null