Solution to "o: In function `__vector_11': multiple definition (...)"

#if 0
SIGNAL(SIG_OUTPUT_COMPARE1A)
{
  #if MOTOR_STYLE == 1
    //do encoder stuff here.
  #else
    //increment our index
    if (motor1_dir == MC_FORWARD)
      stepper_index = (stepper_index - 1) % 8;
    else
      stepper_index = (stepper_index + 1) % 8;

    //coil 1
    digitalWrite(MOTOR_1_DIR_PIN,   coil_a_direction & (1 << stepper_index));
    if (coil_a_enabled & (1 << stepper_index))
      analogWrite(MOTOR_1_SPEED_PIN, stepper_high_pwm);
    else
      analogWrite(MOTOR_1_SPEED_PIN, stepper_low_pwm);

    //coil 2
    digitalWrite(MOTOR_2_DIR_PIN,   coil_b_direction & (1 << stepper_index));
    if (coil_b_enabled & (1 << stepper_index))
      analogWrite(MOTOR_2_SPEED_PIN, stepper_high_pwm);
    else
      analogWrite(MOTOR_2_SPEED_PIN, stepper_low_pwm);
  #endif
}