boards/native: allow to use ZEP instead of tap

If `native` is compiled with `USEMODULE=socket_zep` and networking,
don't also include `netdev_tap` automatically.

This mirrors the behavior on nrf52 and esp* where the default netdev
can be 'overwritten' by another option.

boards/native/Makefile.dep

@@ -1,5 +1,7 @@
 ifneq (,$(filter netdev_default,$(USEMODULE)))
-  USEMODULE += netdev_tap
+  ifeq (,$(filter socket_zep,$(USEMODULE)))
+    USEMODULE += netdev_tap
+  endif
 endif
 
 ifneq (,$(filter mtd,$(USEMODULE)))

boards/native/Makefile.include

@@ -69,7 +69,7 @@ endif
 LINKFLAGS += -ffunction-sections
 
 # set the tap interface for term/valgrind
-ifneq (,$(filter netdev_default,$(USEMODULE)))
+ifneq (,$(filter netdev_tap,$(USEMODULE)))
   PORT ?= tap0
 endif
 

examples/gnrc_border_router/Makefile.board.dep

@@ -13,6 +13,7 @@ ifeq (,$(filter native,$(BOARD)))
     endif
   endif
 else
+  USEMODULE += netdev_tap
   USEMODULE += socket_zep
   USEMODULE += socket_zep_hello
 endif

tests/gnrc_dhcpv6_client_6lbr/Makefile.board.dep

@@ -1,5 +1,6 @@
 # Put board specific dependencies here
 ifeq (native,$(BOARD))
+  USEMODULE += netdev_tap
   USEMODULE += socket_zep
 else
   USEMODULE += stdio_ethos