build: do not assume that gcc-{ar,ranlib,nm} is usable with an external toolchain

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@43911 3c298f89-4303-0410-b956-a3cf2f4a3e73

rules.mk

@@ -192,7 +192,7 @@ HOST_CPPFLAGS:=-I$(STAGING_DIR_HOST)/include -I$(STAGING_DIR_HOST)/usr/include
 HOST_CFLAGS:=-O2 $(HOST_CPPFLAGS)
 HOST_LDFLAGS:=-L$(STAGING_DIR_HOST)/lib -L$(STAGING_DIR_HOST)/usr/lib
 
-ifeq ($(CONFIG_GCC_VERSION_4_4)$(CONFIG_GCC_VERSION_4_6),)
+ifeq ($(CONFIG_GCC_VERSION_4_4)$(CONFIG_GCC_VERSION_4_6)$(CONFIG_EXTERNAL_TOOLCHAIN),)
   TARGET_AR:=$(TARGET_CROSS)gcc-ar
   TARGET_RANLIB:=$(TARGET_CROSS)gcc-ranlib
   TARGET_NM:=$(TARGET_CROSS)gcc-nm