Someone

CC = gcc
OPT = -fPIC -O3 -Wall
objects = finale.o helper.o file.o
program = xax-prog.so

$(program): $(objects) 
	$(CC) -shared -Wl -o $@ $^

finale.o: finale.c 
	$(CC) $(OPT) -c $^

helper.o: helper.c 
	$(CC) $(OPT) -c $^

file.o: file.c
	$(CC) $(OPT) -c $^

clean:
	rm -f $(objects) 
	rm -f $(program)