SANDBOX_DIR_LIST := $(filter-out ./include/,$(sort $(dir $(wildcard ./*/.))))

all:
	@for prog in $(SANDBOX_DIR_LIST); do \
		$(MAKE) -C $$prog; \
	done

clean:
	@for prog in $(SANDBOX_DIR_LIST); do \
		$(MAKE) -C $$prog clean; \
	done

.PHONY: all clean