Universelle CAN Bibliothek: undefined reference to `can_init'

#include <avr/io.h>

#include <avr/interrupt.h>

#include <stdlib.h>

#include "can.h"

#include "config.h"

int main (void) {

  //enable the global interrupts

  sei();

  do{

    // initialisieren des MCP2515

    can_init(BITRATE_125_KBPS);

    // erzeuge eine Testnachricht

    can_t msg;

    msg.id = 0x123456;

    msg.flags.rtr = 0;

    msg.length = 4;

    msg.data[0] = 0xde;

    msg.data[1] = 0xad;

    msg.data[2] = 0xbe;

    msg.data[3] = 0xef;

    // Nachricht verschicken

    can_send_message(&msg);

  } while (1);

return 0;

}

##############################################################################

# Makefile for the project CAN_OBD

###############################################################################

## General Flags

PROJECT = CAN_OBD

MCU = atmega32

TARGET = CAN_OBD.elf

CC = avr-gcc

CPP = avr-g++

## Options common to compile, link and assembly rules

COMMON = -mmcu=$(MCU)

## Compile options common for all C compilation units.

CFLAGS = $(COMMON)

CFLAGS += -Wall -gdwarf-2 -std=gnu99                   -DF_CPU=16000000UL -Os -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums

CFLAGS += -MD -MP -MT $(*F).o -MF dep/$(@F).d 

## Assembly specific flags

ASMFLAGS = $(COMMON)

ASMFLAGS += $(CFLAGS)

ASMFLAGS += -x assembler-with-cpp -Wa,-gdwarf2

## Linker flags

LDFLAGS = $(COMMON)

LDFLAGS +=  -Wl,-Map=CAN_OBD.map

LDFLAGS += -L. -lcan        

## Intel Hex file production flags

HEX_FLASH_FLAGS = -R .eeprom -R .fuse -R .lock -R .signature

HEX_EEPROM_FLAGS = -j .eeprom

HEX_EEPROM_FLAGS += --set-section-flags=.eeprom="alloc,load"

HEX_EEPROM_FLAGS += --change-section-lma .eeprom=0 --no-change-warnings

## Objects that must be built in order to link

OBJECTS = main.o 

## Objects explicitly added by the user

LINKONLYOBJECTS = 

## Build

all: $(TARGET) CAN_OBD.hex CAN_OBD.eep CAN_OBD.lss size

## Compile

main.o: ../main.c

  $(CC) $(INCLUDES) $(CFLAGS) -c  $<

##Link

$(TARGET): $(OBJECTS)

   $(CC) $(LDFLAGS) $(OBJECTS) $(LINKONLYOBJECTS) $(LIBDIRS) $(LIBS) -o $(TARGET)

%.hex: $(TARGET)

  avr-objcopy -O ihex $(HEX_FLASH_FLAGS)  $< $@

%.eep: $(TARGET)

  -avr-objcopy $(HEX_EEPROM_FLAGS) -O ihex $< $@ || exit 0

%.lss: $(TARGET)

  avr-objdump -h -S $< > $@

size: ${TARGET}

  @echo

  @avr-size -C --mcu=${MCU} ${TARGET}

## Clean target

.PHONY: clean

clean:

  -rm -rf $(OBJECTS) CAN_OBD.elf dep/* CAN_OBD.hex CAN_OBD.eep CAN_OBD.lss CAN_OBD.map

## Other dependencies

-include $(shell mkdir dep 2>NUL) $(wildcard dep/*)