busybox: fix busybox-menuconfig after 69df644f5

Closes #3109

Pass the correct -C <dir> option to make menuconfig.

Signed-off-by: Kim Jae-hui <twinkle.j4k@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

CHANGES

@@ -44,6 +44,7 @@
 	#2965: Broken linkage to xkbcomp (blocking X server startup)
 	#2983: xlib_libX11 build failed
 	#3007: kexec doesn't build: Missing regdef.h file
+	#3109: abnormal `make busybox-menuconfig`
 
 2010.11, Released November 30th, 2010:
 

package/busybox/busybox.mk

@@ -151,7 +151,7 @@ endef
 $(eval $(call GENTARGETS,package,busybox))
 
 busybox-menuconfig:	$(BUSYBOX_DIR)/.stamp_extracted
-	$(BUSYBOX_MAKE_ENV) $(MAKE) $(BUSYBOX_MAKE_OPTS) -C $(@D) menuconfig
+	$(BUSYBOX_MAKE_ENV) $(MAKE) $(BUSYBOX_MAKE_OPTS) -C $(BUSYBOX_DIR) menuconfig
 	rm -f $(BUSYBOX_DIR)/.stamp_built
 	rm -f $(BUSYBOX_DIR)/.stamp_target_installed