boards/native: only one CAN_DLL by default

boards/native/Makefile.dep

@@ -10,9 +10,6 @@ endif
 
 ifneq (,$(filter periph_can,$(FEATURES_USED)))
   USEPKG += libsocketcan
-  ifeq ($(OS),Linux)
-    CFLAGS += -DCAN_DLL_NUMOF=2
-  endif
 endif
 
 # default to using littlefs2 on the virtual flash

cpu/native/include/can_params.h

@@ -30,8 +30,12 @@ extern "C" {
  * @brief Default parameters (device names)
  */
 static const candev_params_t candev_params[] = {
+#if CAN_DLL_NUMOF >= 1
     { .name = "can0", },
+#endif
+#if CAN_DLL_NUMOF >= 2
     { .name = "can1", },
+#endif
 };
 
 #ifdef __cplusplus

cpu/native/include/candev_linux.h

@@ -31,6 +31,7 @@ extern "C" {
 
 #include <stdbool.h>
 
+#include "can/device.h"
 #include "can/candev.h"
 #include "mutex.h"