OBJECTS = main.o
TARGET = hello

all: $(TARGET)

$(TARGET): $(OBJECTS)
	$(CC) -o $@ $^

main.o: | new_header
main.o: version.h

new_header:
	@sed -e "s/<version>/$$(git describe)/g" \
		<version.h.in> version.h.tmp
	@if diff -q version.h.tmp version.h > /dev/null 2>&1; \
		then \
			rm version.h.tmp; \
		else \
			echo "version.h.in => version.h" ; \
			mv version.h.tmp version.h;\
		fi

clean:
	rm -f $(TARGET) $(OBJECTS) version.h

.PHONY: all clean