flit: Allow generation from outside

Makefile

@@ -70,16 +70,18 @@ FLIT_CFG ?= $(shell find util -name "*.hjson")
 FLIT_SRC ?= $(patsubst util/%_cfg.hjson,src/floo_%_pkg.sv,$(FLIT_CFG))
 FLIT_GEN ?= util/flit_gen.py
 FLIT_TPL ?= util/floo_flit_pkg.sv.mako
+FLIT_OUT_DIR ?= src
+FLIT_CFG_DIR ?= util
 
 .PHONY: sources clean-sources
 
 sources: $(FLIT_SRC)
-src/floo_%_pkg.sv: util/%_cfg.hjson $(FLIT_GEN) $(FLIT_TPL)
-	./util/flit_gen.py -c $< > $@
+$(FLIT_OUT_DIR)/floo_%_pkg.sv: $(FLIT_CFG_DIR)/%_cfg.hjson $(FLIT_GEN) $(FLIT_TPL)
+	$(FLIT_GEN) -c $< > $@
 	$(VERIBLE_FMT) --inplace --try_wrap_long_lines $@
 
 clean-sources:
-	rm -f src/floo_*_pkg.sv
+	rm $(FLIT_SRC)
 
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 # Traffic Generation #