toolchain/binutils: fill in missing GRAPHITE_CONFIGURE

This var is used further down, but it's empty.
Fix that with the very same values gcc uses.

Signed-off-by: Andre Heider <a.heider@gmail.com>

toolchain/binutils/Makefile

@@ -37,6 +37,12 @@ PATCH_DIR:=./patches/$(PKG_VERSION)
 
 include $(INCLUDE_DIR)/toolchain-build.mk
 
+ifdef CONFIG_GCC_USE_GRAPHITE
+  GRAPHITE_CONFIGURE:= --with-isl=$(STAGING_DIR_HOST)
+else
+  GRAPHITE_CONFIGURE:= --without-isl --without-cloog
+endif
+
 HOST_CONFIGURE_ARGS = \
 	--prefix=$(TOOLCHAIN_DIR) \
 	--build=$(GNU_HOST_NAME) \