1sub_dirs = $(wildcard */) 2 3.PHONY: clean 4clean: 5 @list='$(sub_dirs)'; for subdir in $$list; do \ 6 $(MAKE) -C $$subdir clean;\ 7 done 8 9.PHONY: fmt 10fmt: 11 @list='$(sub_dirs)'; for subdir in $$list; do \ 12 FMT_CHECK=$(FMT_CHECK) $(MAKE) -C $$subdir fmt;\ 13 done 14