why ld return with error?

[ali hagigat]

I have the following files:
prog3.c
#include <stdio.h>
main(){
	printf("uuuuuu\n");
}
prog3.ld
ASSERT(1,"there is not an error");
Then :
gcc -c prog3.c -o prog3.o
ld prog3.o prog3.ld -o prog3

ld: warning: cannot find entry symbol _start; defaulting to 0000000008048074
prog3.o: In function `main':
prog3.c:(.text+0x11): undefined reference to `puts'
------------------------------------------------------------------------
I want to force gcc (or ld) to use its built-in functions as printf
and puts(not to use the standard library functions like libc.a or
libc.so). how can i do it?