头文件greeting.h,greeting2.h、自定义函数文件greeting.c,greeting2.c、主函数文件myapp.c。需要编写一个makefile文件

all: myapp

myapp: myapp.o greeting.o greeting2.o
gcc myapp.o greeting.o greeting2.o -o myapp

myapp.o: myapp.c greeting.h greeting2.h
gcc -c myapp.c

greeting.o: greeting.c greeting.h
gcc -c greeting.c

greeting2.o: greeting2.c greeting2.h
gcc -c greeting2.c

clean:
rm *.o myapp