avr-gcc bindet iom8.h nicht ein?

#include <avr/io.h>

#include <avr/interrupt.h>

#include <stdint.h>

int main(void){

        DDRA = 0xFF;

        PORTA = 0x00;

        while (1);

}

$ avr-gcc -g -Os -mmcu=atmega8 -c main.c

main.c: In function ‘main’:

main.c:10: error: ‘DDRA’ undeclared (first use in this function)

main.c:10: error: (Each undeclared identifier is reported only once

main.c:10: error: for each function it appears in.)

main.c:11: error: ‘PORTA’ undeclared (first use in this function)