Linux Makefile 脚本：同时编译四个文件

.PHONY: all

all: program

program: file1.o file2.o file3.o file4.o gcc -o program file1.o file2.o file3.o file4.o

file1.o: file1.c gcc -c file1.c

file2.o: file2.c gcc -c file2.c

file3.o: file3.c gcc -c file3.c

file4.o: file4.c gcc -c file4.c

clean: rm -f *.o program